fix(routing): net.IPNet to netip.Prefix conversion

fix(firewall): prevent IP family mix in acceptOutputFromIPToSubnet
2023-05-22 05:56:27 +00:00 · 2023-05-21 18:06:18 +00:00
164 changed files with 56566 additions and 122080 deletions
--- a/.devcontainer/README.md
+++ b/.devcontainer/README.md
@@ -9,21 +9,17 @@ It works on Linux, Windows and OSX.
 - [VS code](https://code.visualstudio.com/download) installed
 - [VS code remote containers extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers) installed
 - [Docker](https://www.docker.com/products/docker-desktop) installed and running
+    - If you don't use Linux or WSL 2, share your home directory `~/` and the directory of your project with Docker Desktop
 - [Docker Compose](https://docs.docker.com/compose/install/) installed
+- Ensure your host has the following and that they are accessible by Docker:
+    - `~/.ssh` directory
+    - `~/.gitconfig` file (can be empty)

 ## Setup

-1. Create the following files on your host if you don't have them:
-
-    ```sh
-    touch ~/.gitconfig ~/.zsh_history
-    ```
-
-    Note that the development container will create the empty directories `~/.docker`, `~/.ssh` and `~/.kube` if you don't have them.
-
-1. **For Docker on OSX or Windows without WSL**: ensure your home directory `~` is accessible by Docker.
 1. Open the command palette in Visual Studio Code (CTRL+SHIFT+P).
 1. Select `Remote-Containers: Open Folder in Container...` and choose the project directory.
+1. For Docker running on Windows HyperV, if you want to use SSH keys, bind mount them at `/tmp/.ssh` by changing the `volumes` section in the [docker-compose.yml](docker-compose.yml).

 ## Customization

@@ -33,9 +29,13 @@ You can make changes to the [Dockerfile](Dockerfile) and then rebuild the image.

 ```Dockerfile
 FROM qmcgaw/godevcontainer
+USER root
 RUN apk add curl
+USER vscode
 ```

+Note that you may need to use `USER root` to build as root, and then change back to `USER vscode`.
+
 To rebuild the image, either:

 - With VSCode through the command palette, select `Remote-Containers: Rebuild and reopen in container`
@@ -47,11 +47,11 @@ You can customize **settings** and **extensions** in the [devcontainer.json](dev

 ### Entrypoint script

-You can bind mount a shell script to `/root/.welcome.sh` to replace the [current welcome script](shell/.welcome.sh).
+You can bind mount a shell script to `/home/vscode/.welcome.sh` to replace the [current welcome script](shell/.welcome.sh).

 ### Publish a port

-To access a port from your host to your development container, publish a port in [docker-compose.yml](docker-compose.yml). You can also now do it directly with VSCode without restarting the container.
+To access a port from your host to your development container, publish a port in [docker-compose.yml](docker-compose.yml).

 ### Run other services

--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -1,73 +1,82 @@
-{
-    "name": "gluetun-dev",
-    "dockerComposeFile": [
-        "docker-compose.yml"
-    ],
-    "service": "vscode",
-    "runServices": [
-        "vscode"
-    ],
-    "shutdownAction": "stopCompose",
-    "postCreateCommand": "~/.windows.sh && go mod download && go mod tidy",
-    "workspaceFolder": "/workspace",
-    // "overrideCommand": "",
-    "customizations": {
-        "vscode": {
-            "extensions": [
-                "golang.go",
-                "eamodio.gitlens", // IDE Git information
-                "davidanson.vscode-markdownlint",
-                "ms-azuretools.vscode-docker", // Docker integration and linting
-                "shardulm94.trailing-spaces", // Show trailing spaces
-                "Gruntfuggly.todo-tree", // Highlights TODO comments
-                "bierner.emojisense", // Emoji sense for markdown
-                "stkb.rewrap", // rewrap comments after n characters on one line
-                "vscode-icons-team.vscode-icons", // Better file extension icons
-                "github.vscode-pull-request-github", // Github interaction
-                "redhat.vscode-yaml", // Kubernetes, Drone syntax highlighting
-                "bajdzis.vscode-database", // Supports connections to mysql or postgres, over SSL, socked
-                "IBM.output-colorizer", // Colorize your output/test logs
-                "github.copilot" // AI code completion
-            ],
-            "settings": {
-                "files.eol": "\n",
-                "remote.extensionKind": {
-                    "ms-azuretools.vscode-docker": "workspace"
-                },
-                "go.useLanguageServer": true,
-                "[go]": {
-                    "editor.codeActionsOnSave": {
-                        "source.organizeImports": true
-                    }
-                },
-                "[go.mod]": {
-                    "editor.codeActionsOnSave": {
-                        "source.organizeImports": true
-                    }
-                },
-                "gopls": {
-                    "usePlaceholders": false,
-                    "staticcheck": true
-                },
-                "go.lintTool": "golangci-lint",
-                "go.lintOnSave": "package",
-                "editor.formatOnSave": true,
-                "go.buildTags": "linux",
-                "go.toolsEnvVars": {
-                    "CGO_ENABLED": "0"
-                },
-                "go.testEnvVars": {
-                    "CGO_ENABLED": "1"
-                },
-                "go.testFlags": [
-                    "-v",
-                    "-race"
-                ],
-                "go.testTimeout": "10s",
-                "go.coverOnSingleTest": true,
-                "go.coverOnSingleTestFile": true,
-                "go.coverOnTestPackage": true
-            }
-        }
-    }
+{
+    "name": "gluetun-dev",
+    "dockerComposeFile": [
+        "docker-compose.yml"
+    ],
+    "service": "vscode",
+    "runServices": [
+        "vscode"
+    ],
+    "shutdownAction": "stopCompose",
+    "postCreateCommand": "source ~/.windows.sh && go mod download && go mod tidy",
+    "workspaceFolder": "/workspace",
+    "extensions": [
+        "golang.go",
+        "eamodio.gitlens", // IDE Git information
+        "davidanson.vscode-markdownlint",
+        "ms-azuretools.vscode-docker", // Docker integration and linting
+        "shardulm94.trailing-spaces", // Show trailing spaces
+        "Gruntfuggly.todo-tree", // Highlights TODO comments
+        "bierner.emojisense", // Emoji sense for markdown
+        "stkb.rewrap", // rewrap comments after n characters on one line
+        "vscode-icons-team.vscode-icons", // Better file extension icons
+        "github.vscode-pull-request-github", // Github interaction
+        "redhat.vscode-yaml", // Kubernetes, Drone syntax highlighting
+        "bajdzis.vscode-database", // Supports connections to mysql or postgres, over SSL, socked
+        "IBM.output-colorizer", // Colorize your output/test logs
+        "mohsen1.prettify-json", // Prettify JSON data
+        "github.copilot",
+    ],
+    "settings": {
+        "files.eol": "\n",
+        "remote.extensionKind": {
+            "ms-azuretools.vscode-docker": "workspace"
+        },
+        "editor.codeActionsOnSaveTimeout": 3000,
+        "go.useLanguageServer": true,
+        "[go]": {
+            "editor.formatOnSave": true,
+            "editor.codeActionsOnSave": {
+                "source.organizeImports": true,
+            },
+            // Optional: Disable snippets, as they conflict with completion ranking.
+            "editor.snippetSuggestions": "none"
+        },
+        "[go.mod]": {
+            "editor.formatOnSave": true,
+            "editor.codeActionsOnSave": {
+                "source.organizeImports": true,
+            },
+        },
+        "gopls": {
+            "usePlaceholders": false,
+            "staticcheck": true
+        },
+        "go.autocompleteUnimportedPackages": true,
+        "go.gotoSymbol.includeImports": true,
+        "go.gotoSymbol.includeGoroot": true,
+        "go.lintTool": "golangci-lint",
+        "go.buildOnSave": "workspace",
+        "go.lintOnSave": "workspace",
+        "go.vetOnSave": "workspace",
+        "editor.formatOnSave": true,
+        "go.toolsEnvVars": {
+            "GOFLAGS": "-tags=",
+            // "CGO_ENABLED": 1 // for the race detector
+        },
+        "gopls.env": {
+            "GOFLAGS": "-tags="
+        },
+        "go.testEnvVars": {
+            "": ""
+        },
+        "go.testFlags": [
+            "-v",
+            // "-race"
+        ],
+        "go.testTimeout": "10s",
+        "go.coverOnSingleTest": true,
+        "go.coverOnSingleTestFile": true,
+        "go.coverOnTestPackage": true
+    }
 }
--- a/.devcontainer/docker-compose.yml
+++ b/.devcontainer/docker-compose.yml
@@ -1,28 +1,30 @@
-version: "3.7"
-
-services:
-  vscode:
-    build: .
-    volumes:
-      - ../:/workspace
-      # Docker socket to access Docker server
-      - /var/run/docker.sock:/var/run/docker.sock
-      # SSH directory for Linux, OSX and WSL
-      # On Linux and OSX, a symlink /mnt/ssh <-> ~/.ssh is
-      # created in the container. On Windows, files are copied
-      # from /mnt/ssh to ~/.ssh to fix permissions.
-      - ~/.ssh:/mnt/ssh
-      # Shell history persistence
-      - ~/.zsh_history:/root/.zsh_history
-      # Git config
-      - ~/.gitconfig:/root/.gitconfig
-    environment:
-      - TZ=
-    cap_add:
-      # For debugging with dlv
-      - SYS_PTRACE
-      - NET_ADMIN
-    security_opt:
-      # For debugging with dlv
-      - seccomp:unconfined
-    entrypoint: [ "zsh", "-c", "while sleep 1000; do :; done" ]
+version: "3.7"
+
+services:
+  vscode:
+    build: .
+    devices:
+      - /dev/net/tun:/dev/net/tun
+    volumes:
+      - ../:/workspace
+      # Docker socket to access Docker server
+      - /var/run/docker.sock:/var/run/docker.sock
+      # Docker configuration
+      - ~/.docker:/root/.docker
+      # SSH directory for Linux, OSX and WSL
+      # On Linux and OSX, a symlink /mnt/ssh <-> ~/.ssh is
+      # created in the container. On Windows, files are copied
+      # from /mnt/ssh to ~/.ssh to fix permissions.
+      - ~/.ssh:/mnt/ssh
+      # Shell history persistence
+      - ~/.zsh_history:/root/.zsh_history
+    environment:
+      - TZ=
+    cap_add:
+      # For debugging with dlv
+      # - SYS_PTRACE
+      - NET_ADMIN
+    security_opt:
+      # For debugging with dlv
+      - seccomp:unconfined
+    entrypoint: zsh -c "while sleep 1000; do :; done"
--- a/.github/labels.yml
+++ b/.github/labels.yml
@@ -95,9 +95,6 @@
  description: ""

 # Problem category
- name: "Config problem"
-  color: "ffc7ea"
-  description: ""
 - name: "Openvpn"
  color: "ffc7ea"
  description: ""
@@ -110,15 +107,6 @@
 - name: "Firewall"
  color: "ffc7ea"
  description: ""
- name: "Routing"
-  color: "ffc7ea"
-  description: ""
- name: "IPv6"
-  color: "ffc7ea"
-  description: ""
- name: "Port forwarding"
-  color: "ffc7ea"
-  description: ""
 - name: "HTTP proxy"
  color: "ffc7ea"
  description: ""
--- a/.github/workflows/ci-skip.yml
+++ b/.github/workflows/ci-skip.yml
@@ -14,6 +14,8 @@ on:
      - go.mod
      - go.sum
  pull_request:
+    branches:
+      - master
    paths-ignore:
      - .github/workflows/ci.yml
      - cmd/**
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,6 +17,8 @@ on:
      - go.mod
      - go.sum
  pull_request:
+    branches:
+      - master
    paths:
      - .github/workflows/ci.yml
      - cmd/**
@@ -134,7 +136,7 @@ jobs:
        run: echo "::set-output name=value::$(git rev-parse --short HEAD)"

      - name: Build and push final image
-        uses: docker/build-push-action@v4.1.1
+        uses: docker/build-push-action@v4.0.0
        with:
          platforms: linux/amd64,linux/386,linux/arm64,linux/arm/v6,linux/arm/v7,linux/ppc64le
          labels: ${{ steps.meta.outputs.labels }}
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -46,7 +46,6 @@ linters:
    - decorder
    - dogsled
    - dupl
-    - dupword
    - durationcheck
    - errchkjson
    - errname
@@ -55,7 +54,6 @@ linters:
    - exportloopref
    - forcetypeassert
    - gci
-    - gocheckcompilerdirectives
    - gochecknoglobals
    - gochecknoinits
    - gocognit
@@ -70,7 +68,6 @@ linters:
    - gomoddirectives
    - goprintffuncname
    - gosec
-    - gosmopolitan
    - grouper
    - importas
    - interfacebloat
@@ -78,9 +75,7 @@ linters:
    - lll
    - maintidx
    - makezero
-    - mirror
    - misspell
-    - musttag
    - nakedret
    - nestif
    - nilerr
@@ -88,7 +83,6 @@ linters:
    - noctx
    - nolintlint
    - nosprintfhostport
-    - paralleltest
    - prealloc
    - predeclared
    - promlinter
@@ -96,7 +90,6 @@ linters:
    - revive
    - rowserrcheck
    - sqlclosecheck
-    - tagalign
    - tenv
    - thelper
    - tparallel
@@ -105,7 +98,6 @@ linters:
    - usestdlibvars
    - wastedassign
    - whitespace
-    - zerologlint

 run:
  skip-dirs:
--- a/.vscode/extensions.json
+++ b/.vscode/extensions.json
@@ -1,8 +0,0 @@
-{
-  // This list should be kept to the strict minimum
-  // to develop this project.
-  "recommendations": [
-    "golang.go",
-    "davidanson.vscode-markdownlint",
-  ],
-}
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,29 +0,0 @@
-{
-  // The settings should be kept to the strict minimum
-  // to develop this project.
-  "files.eol": "\n",
-  "editor.formatOnSave": true,
-  "go.buildTags": "linux",
-  "go.toolsEnvVars": {
-    "CGO_ENABLED": "0"
-  },
-  "go.testEnvVars": {
-    "CGO_ENABLED": "1"
-  },
-  "go.testFlags": [
-    "-v",
-    "-race"
-  ],
-  "go.testTimeout": "10s",
-  "go.coverOnSingleTest": true,
-  "go.coverOnSingleTestFile": true,
-  "go.coverOnTestPackage": true,
-  "go.useLanguageServer": true,
-  "[go]": {
-    "editor.codeActionsOnSave": {
-      "source.organizeImports": true
-    }
-  },
-  "go.lintTool": "golangci-lint",
-  "go.lintOnSave": "package"
-}
--- a/14
+++ b/14
@@ -1,8 +1,8 @@
-ARG ALPINE_VERSION=3.18
-ARG GO_ALPINE_VERSION=3.18
+ARG ALPINE_VERSION=3.17
+ARG GO_ALPINE_VERSION=3.17
 ARG GO_VERSION=1.20
 ARG XCPUTRANSLATE_VERSION=v0.6.0
-ARG GOLANGCI_LINT_VERSION=v1.53.2
+ARG GOLANGCI_LINT_VERSION=v1.52.2
 ARG MOCKGEN_VERSION=v1.6.0
 ARG BUILDPLATFORM=linux/amd64

@@ -97,7 +97,6 @@ ENV VPN_SERVICE_PROVIDER=pia \
    WIREGUARD_PRESHARED_KEY= \
    WIREGUARD_PUBLIC_KEY= \
    WIREGUARD_ADDRESSES= \
-    WIREGUARD_MTU=1400 \
    WIREGUARD_IMPLEMENTATION=auto \
    # VPN server filtering
    SERVER_REGIONS= \
@@ -200,11 +199,12 @@ EXPOSE 8000/tcp 8888/tcp 8388/tcp 8388/udp
 HEALTHCHECK --interval=5s --timeout=5s --start-period=10s --retries=1 CMD /gluetun-entrypoint healthcheck
 ARG TARGETPLATFORM
 RUN apk add --no-cache --update -l wget && \
-    apk add --no-cache --update -X "https://dl-cdn.alpinelinux.org/alpine/v3.17/main" openvpn\~2.5 && \
-    mv /usr/sbin/openvpn /usr/sbin/openvpn2.5 && \
+    apk add --no-cache --update -X "https://dl-cdn.alpinelinux.org/alpine/v3.12/main" openvpn==2.4.12-r0 && \
+    apk add --no-cache --update -X "https://dl-cdn.alpinelinux.org/alpine/v3.16/main" openssl\~1.1 && \
+    mv /usr/sbin/openvpn /usr/sbin/openvpn2.4 && \
    apk del openvpn && \
    apk add --no-cache --update openvpn ca-certificates iptables ip6tables unbound tzdata && \
-    mv /usr/sbin/openvpn /usr/sbin/openvpn2.6 && \
+    mv /usr/sbin/openvpn /usr/sbin/openvpn2.5 && \
    # Fix vulnerability issue
    apk add --no-cache --update busybox && \
    rm -rf /var/cache/apk/* /etc/unbound/* /usr/sbin/unbound-* /etc/openvpn/*.sh /usr/lib/openvpn/plugins/openvpn-plugin-down-root.so && \
--- a/README.md
+++ b/README.md
@@ -35,8 +35,8 @@ Lightweight swiss-knife-like VPN client to multiple VPN service providers

 ## Quick links

- [Setup](#setup)
- [Features](#features)
+- [Setup](#Setup)
+- [Features](#Features)
 - Problem?
  - [Check the Wiki](https://github.com/qdm12/gluetun/wiki)
  - [Start a discussion](https://github.com/qdm12/gluetun/discussions)
@@ -57,7 +57,7 @@ Lightweight swiss-knife-like VPN client to multiple VPN service providers

 ## Features

- Based on Alpine 3.18 for a small Docker image of 35.6MB
+- Based on Alpine 3.17 for a small Docker image of 42MB
 - Supports: **AirVPN**, **Cyberghost**, **ExpressVPN**, **FastestVPN**, **HideMyAss**, **IPVanish**, **IVPN**, **Mullvad**, **NordVPN**, **Perfect Privacy**, **Privado**, **Private Internet Access**, **PrivateVPN**, **ProtonVPN**, **PureVPN**,  **SlickVPN**, **Surfshark**, **TorGuard**, **VPNSecure.me**, **VPNUnlimited**, **Vyprvpn**, **WeVPN**, **Windscribe** servers
 - Supports OpenVPN for all providers listed
 - Supports Wireguard both kernelspace and userspace
--- a/cmd/gluetun/main.go
+++ b/cmd/gluetun/main.go
@@ -264,8 +264,8 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,

 	err = printVersions(ctx, logger, []printVersionElement{
 		{name: "Alpine", getVersion: alpineConf.Version},
+		{name: "OpenVPN 2.4", getVersion: ovpnConf.Version24},
 		{name: "OpenVPN 2.5", getVersion: ovpnConf.Version25},
-		{name: "OpenVPN 2.6", getVersion: ovpnConf.Version26},
 		{name: "Unbound", getVersion: dnsConf.Version},
 		{name: "IPtables", getVersion: func(ctx context.Context) (version string, err error) {
 			return firewall.Version(ctx, cmder)
@@ -531,29 +531,30 @@ type netLinker interface {
 type Addresser interface {
 	AddrList(link netlink.Link, family int) (
 		addresses []netlink.Addr, err error)
-	AddrReplace(link netlink.Link, addr netlink.Addr) error
+	AddrAdd(link netlink.Link, addr *netlink.Addr) error
 }

 type Router interface {
-	RouteList(family int) (routes []netlink.Route, err error)
-	RouteAdd(route netlink.Route) error
-	RouteDel(route netlink.Route) error
-	RouteReplace(route netlink.Route) error
+	RouteList(link netlink.Link, family int) (
+		routes []netlink.Route, err error)
+	RouteAdd(route *netlink.Route) error
+	RouteDel(route *netlink.Route) error
+	RouteReplace(route *netlink.Route) error
 }

 type Ruler interface {
 	RuleList(family int) (rules []netlink.Rule, err error)
-	RuleAdd(rule netlink.Rule) error
-	RuleDel(rule netlink.Rule) error
+	RuleAdd(rule *netlink.Rule) error
+	RuleDel(rule *netlink.Rule) error
 }

 type Linker interface {
 	LinkList() (links []netlink.Link, err error)
 	LinkByName(name string) (link netlink.Link, err error)
 	LinkByIndex(index int) (link netlink.Link, err error)
-	LinkAdd(link netlink.Link) (linkIndex int, err error)
+	LinkAdd(link netlink.Link) (err error)
 	LinkDel(link netlink.Link) (err error)
-	LinkSetUp(link netlink.Link) (linkIndex int, err error)
+	LinkSetUp(link netlink.Link) (err error)
 	LinkSetDown(link netlink.Link) (err error)
 }

--- a/go.mod
+++ b/go.mod
@@ -3,25 +3,25 @@ module github.com/qdm12/gluetun
 go 1.20

 require (
-	github.com/breml/rootcerts v0.2.11
+	github.com/breml/rootcerts v0.2.10
 	github.com/fatih/color v1.15.0
 	github.com/golang/mock v1.6.0
 	github.com/qdm12/dns v1.11.0
 	github.com/qdm12/golibs v0.0.0-20210822203818-5c568b0777b6
-	github.com/qdm12/gosettings v0.3.0-rc13
 	github.com/qdm12/goshutdown v0.3.0
 	github.com/qdm12/gosplash v0.1.0
 	github.com/qdm12/gotree v0.2.0
-	github.com/qdm12/govalid v0.2.0-rc1
+	github.com/qdm12/govalid v0.1.0
 	github.com/qdm12/log v0.1.0
-	github.com/qdm12/ss-server v0.5.0-rc1
+	github.com/qdm12/ss-server v0.4.0
 	github.com/qdm12/updated v0.0.0-20210603204757-205acfe6937e
-	github.com/stretchr/testify v1.8.4
+	github.com/stretchr/testify v1.8.2
 	github.com/vishvananda/netlink v1.2.1-beta.2
 	github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a
+	golang.org/x/exp v0.0.0-20230519143937-03e91628a987
 	golang.org/x/net v0.10.0
 	golang.org/x/sys v0.8.0
-	golang.org/x/text v0.10.0
+	golang.org/x/text v0.9.0
 	golang.zx2c4.com/wireguard v0.0.0-20230325221338-052af4a8072b
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20230215201556-9c5414ab4bde
 	inet.af/netaddr v0.0.0-20220811202034-502d2d690317
@@ -43,8 +43,7 @@ require (
 	github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae // indirect
 	go4.org/intern v0.0.0-20211027215823-ae77deb06f29 // indirect
 	go4.org/unsafe/assume-no-moving-gc v0.0.0-20230221090011-e4bae7ad2296 // indirect
-	golang.org/x/crypto v0.9.0 // indirect
-	golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 // indirect
+	golang.org/x/crypto v0.6.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
--- a/go.sum
+++ b/go.sum
@@ -4,8 +4,8 @@ github.com/alcortesm/tgz v0.0.0-20161220082320-9c5fe88206d7/go.mod h1:6zEj6s6u/g
 github.com/anmitsu/go-shlex v0.0.0-20161002113705-648efa622239/go.mod h1:2FmKhYUyUczH0OGQWaF5ceTx0UBShxjsH6f8oGKYe2c=
 github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
 github.com/asaskevich/govalidator v0.0.0-20180720115003-f9ffefc3facf/go.mod h1:lB+ZfQJz7igIIfQNfa7Ml4HSf2uFQQRzpGGRXenZAgY=
-github.com/breml/rootcerts v0.2.11 h1:njUAtoyZ6HUXPAPk63tGz0BEZk1/6gyfqK5fTzksHkM=
-github.com/breml/rootcerts v0.2.11/go.mod h1:S/PKh+4d1HUn4HQovEB8hPJZO6pUZYrIhmXBhsegfXw=
+github.com/breml/rootcerts v0.2.10 h1:UGVZ193UTSUASpGtg6pbDwzOd7XQP+at0Ssg1/2E4h8=
+github.com/breml/rootcerts v0.2.10/go.mod h1:24FDtzYMpqIeYC7QzaE8VPRQaFZU5TIUDlyk8qwjD88=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -91,20 +91,18 @@ github.com/qdm12/golibs v0.0.0-20210603202746-e5494e9c2ebb/go.mod h1:15RBzkun0i8
 github.com/qdm12/golibs v0.0.0-20210723175634-a75ca7fd74c2/go.mod h1:6aRbg4Z/bTbm9JfxsGXfWKHi7zsOvPfUTK1S5HuAFKg=
 github.com/qdm12/golibs v0.0.0-20210822203818-5c568b0777b6 h1:bge5AL7cjHJMPz+5IOz5yF01q/l8No6+lIEBieA8gMg=
 github.com/qdm12/golibs v0.0.0-20210822203818-5c568b0777b6/go.mod h1:6aRbg4Z/bTbm9JfxsGXfWKHi7zsOvPfUTK1S5HuAFKg=
-github.com/qdm12/gosettings v0.3.0-rc13 h1:fag+/hFPBUcNk3a5ifUbwNS2VgXFpxindkl8mQNk76U=
-github.com/qdm12/gosettings v0.3.0-rc13/go.mod h1:JRV3opOpHvnKlIA29lKQMdYw1WSMVMfHYLLHPHol5ME=
 github.com/qdm12/goshutdown v0.3.0 h1:pqBpJkdwlZlfTEx4QHtS8u8CXx6pG0fVo6S1N0MpSEM=
 github.com/qdm12/goshutdown v0.3.0/go.mod h1:EqZ46No00kCTZ5qzdd3qIzY6ayhMt24QI8Mh8LVQYmM=
 github.com/qdm12/gosplash v0.1.0 h1:Sfl+zIjFZFP7b0iqf2l5UkmEY97XBnaKkH3FNY6Gf7g=
 github.com/qdm12/gosplash v0.1.0/go.mod h1:+A3fWW4/rUeDXhY3ieBzwghKdnIPFJgD8K3qQkenJlw=
 github.com/qdm12/gotree v0.2.0 h1:+58ltxkNLUyHtATFereAcOjBVfY6ETqRex8XK90Fb/c=
 github.com/qdm12/gotree v0.2.0/go.mod h1:1SdFaqKZuI46U1apbXIf25pDMNnrPuYLEqMF/qL4lY4=
-github.com/qdm12/govalid v0.2.0-rc1 h1:4iYQvU4ibrASgzelsEgZX4JyKX3UTB/DcHObzQ7BXtw=
-github.com/qdm12/govalid v0.2.0-rc1/go.mod h1:/uWzVWMuS71wmbsVnlUxpQiy6EAXqm8eQ2RbyA72roQ=
+github.com/qdm12/govalid v0.1.0 h1:UIFVmuaAg0Q+h0GeyfcFEZ5sQ5KJPvRQwycC1/cqDN8=
+github.com/qdm12/govalid v0.1.0/go.mod h1:CyS/OEQdOvunBgrtIsW93fjd4jBkwZPBjGSpxq3NwA4=
 github.com/qdm12/log v0.1.0 h1:jYBd/xscHYpblzZAd2kjZp2YmuYHjAAfbTViJWxoPTw=
 github.com/qdm12/log v0.1.0/go.mod h1:Vchi5M8uBvHfPNIblN4mjXn/oSbiWguQIbsgF1zdQPI=
-github.com/qdm12/ss-server v0.5.0-rc1 h1:2rJEhDnUUc9AKtvyVu+CrnJwvdEjMaB1zFRQvTUlDPw=
-github.com/qdm12/ss-server v0.5.0-rc1/go.mod h1:IoFYGpVpxfIB/dMTr0PnSegdhV1gEfZLS9Tr1Qn8uRg=
+github.com/qdm12/ss-server v0.4.0 h1:lMMYfDGc9P86Lyvd3+p8lK4hhgHUKDzjZC91FqJYkDU=
+github.com/qdm12/ss-server v0.4.0/go.mod h1:AY0p4huvPUPW+/CiWsJcDgT6sneDryk26VXSccPNCxY=
 github.com/qdm12/updated v0.0.0-20210603204757-205acfe6937e h1:4q+uFLawkaQRq3yARYLsjJPZd2wYwxn4g6G/5v0xW1g=
 github.com/qdm12/updated v0.0.0-20210603204757-205acfe6937e/go.mod h1:UvJRGkZ9XL3/D7e7JiTTVLm1F3Cymd3/gFpD6frEpBo=
 github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3 h1:f/FNXud6gA3MNr8meMVVGxhp+QBTqY91tM8HjEuMjGg=
@@ -113,12 +111,16 @@ github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAm
 github.com/src-d/gcfg v1.4.0/go.mod h1:p/UMsR43ujA89BJY9duynAwIpvqEujIH/jFlfL7jWoI=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/vishvananda/netlink v1.2.1-beta.2 h1:Llsql0lnQEbHj0I1OuKyp8otXp0r3q0mPkuhwHfStVs=
 github.com/vishvananda/netlink v1.2.1-beta.2/go.mod h1:twkDnbuQxJYemMlGd4JFIcuhgX83tXhKS2B/PRMpOho=
 github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae h1:4hwBBUfQCFe3Cym0ZtKyq7L16eZUtYKs+BaHDN6mAns=
@@ -146,10 +148,10 @@ golang.org/x/crypto v0.0.0-20200302210943-78000ba7a073/go.mod h1:LzIPMQfyMNhhGPh
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a/go.mod h1:P+XmwS30IXTQdn5tA2iutPOUgjI07+tq3H3K9MVA1s8=
 golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
-golang.org/x/crypto v0.9.0 h1:LF6fAI+IutBocDJ2OT0Q1g8plpYljMZ4+lty+dsqw3g=
-golang.org/x/crypto v0.9.0/go.mod h1:yrmDGqONDYtNj3tH8X9dzUun2m2lzPa9ngI6/RUPGR0=
-golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 h1:k/i9J1pBpvlfR+9QsetwPyERsqu1GIbi967PQMq3Ivc=
-golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1/go.mod h1:V1LtkGg67GoY2N1AnLN78QLrzxkLyJw7RJb1gzOOz9w=
+golang.org/x/crypto v0.6.0 h1:qfktjS5LUO+fFKeJXZ+ikTRijMmljikvG68fpMMruSc=
+golang.org/x/crypto v0.6.0/go.mod h1:OFC/31mSvZgRz0V1QTNCzfAI1aIRzbiufJtkMIlEp58=
+golang.org/x/exp v0.0.0-20230519143937-03e91628a987 h1:3xJIFvzUFbu4ls0BTBYcgbCGhA63eAOEMxIHugyXJqA=
+golang.org/x/exp v0.0.0-20230519143937-03e91628a987/go.mod h1:V1LtkGg67GoY2N1AnLN78QLrzxkLyJw7RJb1gzOOz9w=
 golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
@@ -204,8 +206,8 @@ golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/text v0.10.0 h1:UpjohKhiEgNc0CSauXmwYftY1+LlaC75SJwh0SgCX58=
-golang.org/x/text v0.10.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/text v0.9.0 h1:2sjJmO8cDvYveuX97RDLsxlyUxLl+GHoLxBiRdHllBE=
+golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0 h1:/5xXl8Y5W96D+TtHSlonuFqGHIWVuyCkGJLwGh9JJFs=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190729092621-ff9f1409240a/go.mod h1:jcCCGcm9btYwXyDqrUWc6MKQKKGJCWEQ3AfLSRIbEuI=
--- a/internal/configuration/settings/dns.go
+++ b/internal/configuration/settings/dns.go
@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"net/netip"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -40,7 +40,7 @@ func (d DNS) validate() (err error) {
 func (d *DNS) Copy() (copied DNS) {
 	return DNS{
 		ServerAddress:  d.ServerAddress,
-		KeepNameserver: gosettings.CopyPointer(d.KeepNameserver),
+		KeepNameserver: helpers.CopyPointer(d.KeepNameserver),
 		DoT:            d.DoT.copy(),
 	}
 }
@@ -48,8 +48,8 @@ func (d *DNS) Copy() (copied DNS) {
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (d *DNS) mergeWith(other DNS) {
-	d.ServerAddress = gosettings.MergeWithValidator(d.ServerAddress, other.ServerAddress)
-	d.KeepNameserver = gosettings.MergeWithPointer(d.KeepNameserver, other.KeepNameserver)
+	d.ServerAddress = helpers.MergeWithIP(d.ServerAddress, other.ServerAddress)
+	d.KeepNameserver = helpers.MergeWithPointer(d.KeepNameserver, other.KeepNameserver)
 	d.DoT.mergeWith(other.DoT)
 }

@@ -57,15 +57,15 @@ func (d *DNS) mergeWith(other DNS) {
 // settings object with any field set in the other
 // settings.
 func (d *DNS) overrideWith(other DNS) {
-	d.ServerAddress = gosettings.OverrideWithValidator(d.ServerAddress, other.ServerAddress)
-	d.KeepNameserver = gosettings.OverrideWithPointer(d.KeepNameserver, other.KeepNameserver)
+	d.ServerAddress = helpers.OverrideWithIP(d.ServerAddress, other.ServerAddress)
+	d.KeepNameserver = helpers.OverrideWithPointer(d.KeepNameserver, other.KeepNameserver)
 	d.DoT.overrideWith(other.DoT)
 }

 func (d *DNS) setDefaults() {
 	localhost := netip.AddrFrom4([4]byte{127, 0, 0, 1})
-	d.ServerAddress = gosettings.DefaultValidator(d.ServerAddress, localhost)
-	d.KeepNameserver = gosettings.DefaultPointer(d.KeepNameserver, false)
+	d.ServerAddress = helpers.DefaultIP(d.ServerAddress, localhost)
+	d.KeepNameserver = helpers.DefaultPointer(d.KeepNameserver, false)
 	d.DoT.setDefaults()
 }

@@ -76,7 +76,7 @@ func (d DNS) String() string {
 func (d DNS) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("DNS settings:")
 	node.Appendf("DNS server address to use: %s", d.ServerAddress)
-	node.Appendf("Keep existing nameserver(s): %s", gosettings.BoolToYesNo(d.KeepNameserver))
+	node.Appendf("Keep existing nameserver(s): %s", helpers.BoolPtrToYesNo(d.KeepNameserver))
 	node.AppendNode(d.DoT.toLinesNode())
 	return node
 }
--- a/internal/configuration/settings/dnsblacklist.go
+++ b/internal/configuration/settings/dnsblacklist.go
@@ -7,7 +7,7 @@ import (
 	"regexp"

 	"github.com/qdm12/dns/pkg/blacklist"
-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -23,9 +23,9 @@ type DNSBlacklist struct {
 }

 func (b *DNSBlacklist) setDefaults() {
-	b.BlockMalicious = gosettings.DefaultPointer(b.BlockMalicious, true)
-	b.BlockAds = gosettings.DefaultPointer(b.BlockAds, false)
-	b.BlockSurveillance = gosettings.DefaultPointer(b.BlockSurveillance, true)
+	b.BlockMalicious = helpers.DefaultPointer(b.BlockMalicious, true)
+	b.BlockAds = helpers.DefaultPointer(b.BlockAds, false)
+	b.BlockSurveillance = helpers.DefaultPointer(b.BlockSurveillance, true)
 }

 var hostRegex = regexp.MustCompile(`^([a-zA-Z0-9]|[a-zA-Z0-9_][a-zA-Z0-9\-_]{0,61}[a-zA-Z0-9_])(\.([a-zA-Z0-9]|[a-zA-Z0-9_][a-zA-Z0-9\-_]{0,61}[a-zA-Z0-9]))*$`) //nolint:lll
@@ -53,34 +53,34 @@ func (b DNSBlacklist) validate() (err error) {

 func (b DNSBlacklist) copy() (copied DNSBlacklist) {
 	return DNSBlacklist{
-		BlockMalicious:       gosettings.CopyPointer(b.BlockMalicious),
-		BlockAds:             gosettings.CopyPointer(b.BlockAds),
-		BlockSurveillance:    gosettings.CopyPointer(b.BlockSurveillance),
-		AllowedHosts:         gosettings.CopySlice(b.AllowedHosts),
-		AddBlockedHosts:      gosettings.CopySlice(b.AddBlockedHosts),
-		AddBlockedIPs:        gosettings.CopySlice(b.AddBlockedIPs),
-		AddBlockedIPPrefixes: gosettings.CopySlice(b.AddBlockedIPPrefixes),
+		BlockMalicious:       helpers.CopyPointer(b.BlockMalicious),
+		BlockAds:             helpers.CopyPointer(b.BlockAds),
+		BlockSurveillance:    helpers.CopyPointer(b.BlockSurveillance),
+		AllowedHosts:         helpers.CopySlice(b.AllowedHosts),
+		AddBlockedHosts:      helpers.CopySlice(b.AddBlockedHosts),
+		AddBlockedIPs:        helpers.CopySlice(b.AddBlockedIPs),
+		AddBlockedIPPrefixes: helpers.CopySlice(b.AddBlockedIPPrefixes),
 	}
 }

 func (b *DNSBlacklist) mergeWith(other DNSBlacklist) {
-	b.BlockMalicious = gosettings.MergeWithPointer(b.BlockMalicious, other.BlockMalicious)
-	b.BlockAds = gosettings.MergeWithPointer(b.BlockAds, other.BlockAds)
-	b.BlockSurveillance = gosettings.MergeWithPointer(b.BlockSurveillance, other.BlockSurveillance)
-	b.AllowedHosts = gosettings.MergeWithSlice(b.AllowedHosts, other.AllowedHosts)
-	b.AddBlockedHosts = gosettings.MergeWithSlice(b.AddBlockedHosts, other.AddBlockedHosts)
-	b.AddBlockedIPs = gosettings.MergeWithSlice(b.AddBlockedIPs, other.AddBlockedIPs)
-	b.AddBlockedIPPrefixes = gosettings.MergeWithSlice(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
+	b.BlockMalicious = helpers.MergeWithPointer(b.BlockMalicious, other.BlockMalicious)
+	b.BlockAds = helpers.MergeWithPointer(b.BlockAds, other.BlockAds)
+	b.BlockSurveillance = helpers.MergeWithPointer(b.BlockSurveillance, other.BlockSurveillance)
+	b.AllowedHosts = helpers.MergeSlices(b.AllowedHosts, other.AllowedHosts)
+	b.AddBlockedHosts = helpers.MergeSlices(b.AddBlockedHosts, other.AddBlockedHosts)
+	b.AddBlockedIPs = helpers.MergeSlices(b.AddBlockedIPs, other.AddBlockedIPs)
+	b.AddBlockedIPPrefixes = helpers.MergeSlices(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
 }

 func (b *DNSBlacklist) overrideWith(other DNSBlacklist) {
-	b.BlockMalicious = gosettings.OverrideWithPointer(b.BlockMalicious, other.BlockMalicious)
-	b.BlockAds = gosettings.OverrideWithPointer(b.BlockAds, other.BlockAds)
-	b.BlockSurveillance = gosettings.OverrideWithPointer(b.BlockSurveillance, other.BlockSurveillance)
-	b.AllowedHosts = gosettings.OverrideWithSlice(b.AllowedHosts, other.AllowedHosts)
-	b.AddBlockedHosts = gosettings.OverrideWithSlice(b.AddBlockedHosts, other.AddBlockedHosts)
-	b.AddBlockedIPs = gosettings.OverrideWithSlice(b.AddBlockedIPs, other.AddBlockedIPs)
-	b.AddBlockedIPPrefixes = gosettings.OverrideWithSlice(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
+	b.BlockMalicious = helpers.OverrideWithPointer(b.BlockMalicious, other.BlockMalicious)
+	b.BlockAds = helpers.OverrideWithPointer(b.BlockAds, other.BlockAds)
+	b.BlockSurveillance = helpers.OverrideWithPointer(b.BlockSurveillance, other.BlockSurveillance)
+	b.AllowedHosts = helpers.OverrideWithSlice(b.AllowedHosts, other.AllowedHosts)
+	b.AddBlockedHosts = helpers.OverrideWithSlice(b.AddBlockedHosts, other.AddBlockedHosts)
+	b.AddBlockedIPs = helpers.OverrideWithSlice(b.AddBlockedIPs, other.AddBlockedIPs)
+	b.AddBlockedIPPrefixes = helpers.OverrideWithSlice(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
 }

 func (b DNSBlacklist) ToBlacklistFormat() (settings blacklist.BuilderSettings, err error) {
@@ -102,9 +102,9 @@ func (b DNSBlacklist) String() string {
 func (b DNSBlacklist) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("DNS filtering settings:")

-	node.Appendf("Block malicious: %s", gosettings.BoolToYesNo(b.BlockMalicious))
-	node.Appendf("Block ads: %s", gosettings.BoolToYesNo(b.BlockAds))
-	node.Appendf("Block surveillance: %s", gosettings.BoolToYesNo(b.BlockSurveillance))
+	node.Appendf("Block malicious: %s", helpers.BoolPtrToYesNo(b.BlockMalicious))
+	node.Appendf("Block ads: %s", helpers.BoolPtrToYesNo(b.BlockAds))
+	node.Appendf("Block surveillance: %s", helpers.BoolPtrToYesNo(b.BlockSurveillance))

 	if len(b.AllowedHosts) > 0 {
 		allowedHostsNode := node.Appendf("Allowed hosts:")
--- a/internal/configuration/settings/dot.go
+++ b/internal/configuration/settings/dot.go
@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"time"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -54,8 +54,8 @@ func (d DoT) validate() (err error) {

 func (d *DoT) copy() (copied DoT) {
 	return DoT{
-		Enabled:      gosettings.CopyPointer(d.Enabled),
-		UpdatePeriod: gosettings.CopyPointer(d.UpdatePeriod),
+		Enabled:      helpers.CopyPointer(d.Enabled),
+		UpdatePeriod: helpers.CopyPointer(d.UpdatePeriod),
 		Unbound:      d.Unbound.copy(),
 		Blacklist:    d.Blacklist.copy(),
 	}
@@ -64,8 +64,8 @@ func (d *DoT) copy() (copied DoT) {
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (d *DoT) mergeWith(other DoT) {
-	d.Enabled = gosettings.MergeWithPointer(d.Enabled, other.Enabled)
-	d.UpdatePeriod = gosettings.MergeWithPointer(d.UpdatePeriod, other.UpdatePeriod)
+	d.Enabled = helpers.MergeWithPointer(d.Enabled, other.Enabled)
+	d.UpdatePeriod = helpers.MergeWithPointer(d.UpdatePeriod, other.UpdatePeriod)
 	d.Unbound.mergeWith(other.Unbound)
 	d.Blacklist.mergeWith(other.Blacklist)
 }
@@ -74,16 +74,16 @@ func (d *DoT) mergeWith(other DoT) {
 // settings object with any field set in the other
 // settings.
 func (d *DoT) overrideWith(other DoT) {
-	d.Enabled = gosettings.OverrideWithPointer(d.Enabled, other.Enabled)
-	d.UpdatePeriod = gosettings.OverrideWithPointer(d.UpdatePeriod, other.UpdatePeriod)
+	d.Enabled = helpers.OverrideWithPointer(d.Enabled, other.Enabled)
+	d.UpdatePeriod = helpers.OverrideWithPointer(d.UpdatePeriod, other.UpdatePeriod)
 	d.Unbound.overrideWith(other.Unbound)
 	d.Blacklist.overrideWith(other.Blacklist)
 }

 func (d *DoT) setDefaults() {
-	d.Enabled = gosettings.DefaultPointer(d.Enabled, true)
+	d.Enabled = helpers.DefaultPointer(d.Enabled, true)
 	const defaultUpdatePeriod = 24 * time.Hour
-	d.UpdatePeriod = gosettings.DefaultPointer(d.UpdatePeriod, defaultUpdatePeriod)
+	d.UpdatePeriod = helpers.DefaultPointer(d.UpdatePeriod, defaultUpdatePeriod)
 	d.Unbound.setDefaults()
 	d.Blacklist.setDefaults()
 }
@@ -95,7 +95,7 @@ func (d DoT) String() string {
 func (d DoT) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("DNS over TLS settings:")

-	node.Appendf("Enabled: %s", gosettings.BoolToYesNo(d.Enabled))
+	node.Appendf("Enabled: %s", helpers.BoolPtrToYesNo(d.Enabled))
 	if !*d.Enabled {
 		return node
 	}
--- a/internal/configuration/settings/firewall.go
+++ b/internal/configuration/settings/firewall.go
@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"net/netip"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -40,11 +40,11 @@ func hasZeroPort(ports []uint16) (has bool) {

 func (f *Firewall) copy() (copied Firewall) {
 	return Firewall{
-		VPNInputPorts:   gosettings.CopySlice(f.VPNInputPorts),
-		InputPorts:      gosettings.CopySlice(f.InputPorts),
-		OutboundSubnets: gosettings.CopySlice(f.OutboundSubnets),
-		Enabled:         gosettings.CopyPointer(f.Enabled),
-		Debug:           gosettings.CopyPointer(f.Debug),
+		VPNInputPorts:   helpers.CopySlice(f.VPNInputPorts),
+		InputPorts:      helpers.CopySlice(f.InputPorts),
+		OutboundSubnets: helpers.CopySlice(f.OutboundSubnets),
+		Enabled:         helpers.CopyPointer(f.Enabled),
+		Debug:           helpers.CopyPointer(f.Debug),
 	}
 }

@@ -53,27 +53,27 @@ func (f *Firewall) copy() (copied Firewall) {
 // It merges values of slices together, even if they
 // are set in the receiver settings.
 func (f *Firewall) mergeWith(other Firewall) {
-	f.VPNInputPorts = gosettings.MergeWithSlice(f.VPNInputPorts, other.VPNInputPorts)
-	f.InputPorts = gosettings.MergeWithSlice(f.InputPorts, other.InputPorts)
-	f.OutboundSubnets = gosettings.MergeWithSlice(f.OutboundSubnets, other.OutboundSubnets)
-	f.Enabled = gosettings.MergeWithPointer(f.Enabled, other.Enabled)
-	f.Debug = gosettings.MergeWithPointer(f.Debug, other.Debug)
+	f.VPNInputPorts = helpers.MergeSlices(f.VPNInputPorts, other.VPNInputPorts)
+	f.InputPorts = helpers.MergeSlices(f.InputPorts, other.InputPorts)
+	f.OutboundSubnets = helpers.MergeSlices(f.OutboundSubnets, other.OutboundSubnets)
+	f.Enabled = helpers.MergeWithPointer(f.Enabled, other.Enabled)
+	f.Debug = helpers.MergeWithPointer(f.Debug, other.Debug)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (f *Firewall) overrideWith(other Firewall) {
-	f.VPNInputPorts = gosettings.OverrideWithSlice(f.VPNInputPorts, other.VPNInputPorts)
-	f.InputPorts = gosettings.OverrideWithSlice(f.InputPorts, other.InputPorts)
-	f.OutboundSubnets = gosettings.OverrideWithSlice(f.OutboundSubnets, other.OutboundSubnets)
-	f.Enabled = gosettings.OverrideWithPointer(f.Enabled, other.Enabled)
-	f.Debug = gosettings.OverrideWithPointer(f.Debug, other.Debug)
+	f.VPNInputPorts = helpers.OverrideWithSlice(f.VPNInputPorts, other.VPNInputPorts)
+	f.InputPorts = helpers.OverrideWithSlice(f.InputPorts, other.InputPorts)
+	f.OutboundSubnets = helpers.OverrideWithSlice(f.OutboundSubnets, other.OutboundSubnets)
+	f.Enabled = helpers.OverrideWithPointer(f.Enabled, other.Enabled)
+	f.Debug = helpers.OverrideWithPointer(f.Debug, other.Debug)
 }

 func (f *Firewall) setDefaults() {
-	f.Enabled = gosettings.DefaultPointer(f.Enabled, true)
-	f.Debug = gosettings.DefaultPointer(f.Debug, false)
+	f.Enabled = helpers.DefaultPointer(f.Enabled, true)
+	f.Debug = helpers.DefaultPointer(f.Debug, false)
 }

 func (f Firewall) String() string {
@@ -83,7 +83,7 @@ func (f Firewall) String() string {
 func (f Firewall) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Firewall settings:")

-	node.Appendf("Enabled: %s", gosettings.BoolToYesNo(f.Enabled))
+	node.Appendf("Enabled: %s", helpers.BoolPtrToYesNo(f.Enabled))
 	if !*f.Enabled {
 		return node
 	}
--- a/internal/configuration/settings/health.go
+++ b/internal/configuration/settings/health.go
@@ -5,7 +5,7 @@ import (
 	"os"
 	"time"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 	"github.com/qdm12/govalid/address"
 )
@@ -37,7 +37,7 @@ type Health struct {

 func (h Health) Validate() (err error) {
 	uid := os.Getuid()
-	err = address.Validate(h.ServerAddress,
+	_, err = address.Validate(h.ServerAddress,
 		address.OptionListening(uid))
 	if err != nil {
 		return fmt.Errorf("server listening address is not valid: %w", err)
@@ -65,11 +65,11 @@ func (h *Health) copy() (copied Health) {
 // MergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (h *Health) MergeWith(other Health) {
-	h.ServerAddress = gosettings.MergeWithString(h.ServerAddress, other.ServerAddress)
-	h.ReadHeaderTimeout = gosettings.MergeWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = gosettings.MergeWithNumber(h.ReadTimeout, other.ReadTimeout)
-	h.TargetAddress = gosettings.MergeWithString(h.TargetAddress, other.TargetAddress)
-	h.SuccessWait = gosettings.MergeWithNumber(h.SuccessWait, other.SuccessWait)
+	h.ServerAddress = helpers.MergeWithString(h.ServerAddress, other.ServerAddress)
+	h.ReadHeaderTimeout = helpers.MergeWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.MergeWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.TargetAddress = helpers.MergeWithString(h.TargetAddress, other.TargetAddress)
+	h.SuccessWait = helpers.MergeWithNumber(h.SuccessWait, other.SuccessWait)
 	h.VPN.mergeWith(other.VPN)
 }

@@ -77,23 +77,23 @@ func (h *Health) MergeWith(other Health) {
 // settings object with any field set in the other
 // settings.
 func (h *Health) OverrideWith(other Health) {
-	h.ServerAddress = gosettings.OverrideWithString(h.ServerAddress, other.ServerAddress)
-	h.ReadHeaderTimeout = gosettings.OverrideWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = gosettings.OverrideWithNumber(h.ReadTimeout, other.ReadTimeout)
-	h.TargetAddress = gosettings.OverrideWithString(h.TargetAddress, other.TargetAddress)
-	h.SuccessWait = gosettings.OverrideWithNumber(h.SuccessWait, other.SuccessWait)
+	h.ServerAddress = helpers.OverrideWithString(h.ServerAddress, other.ServerAddress)
+	h.ReadHeaderTimeout = helpers.OverrideWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.OverrideWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.TargetAddress = helpers.OverrideWithString(h.TargetAddress, other.TargetAddress)
+	h.SuccessWait = helpers.OverrideWithNumber(h.SuccessWait, other.SuccessWait)
 	h.VPN.overrideWith(other.VPN)
 }

 func (h *Health) SetDefaults() {
-	h.ServerAddress = gosettings.DefaultString(h.ServerAddress, "127.0.0.1:9999")
+	h.ServerAddress = helpers.DefaultString(h.ServerAddress, "127.0.0.1:9999")
 	const defaultReadHeaderTimeout = 100 * time.Millisecond
-	h.ReadHeaderTimeout = gosettings.DefaultNumber(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
+	h.ReadHeaderTimeout = helpers.DefaultNumber(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
 	const defaultReadTimeout = 500 * time.Millisecond
-	h.ReadTimeout = gosettings.DefaultNumber(h.ReadTimeout, defaultReadTimeout)
-	h.TargetAddress = gosettings.DefaultString(h.TargetAddress, "cloudflare.com:443")
+	h.ReadTimeout = helpers.DefaultNumber(h.ReadTimeout, defaultReadTimeout)
+	h.TargetAddress = helpers.DefaultString(h.TargetAddress, "cloudflare.com:443")
 	const defaultSuccessWait = 5 * time.Second
-	h.SuccessWait = gosettings.DefaultNumber(h.SuccessWait, defaultSuccessWait)
+	h.SuccessWait = helpers.DefaultNumber(h.SuccessWait, defaultSuccessWait)
 	h.VPN.setDefaults()
 }

--- a/internal/configuration/settings/healthywait.go
+++ b/internal/configuration/settings/healthywait.go
@@ -3,7 +3,7 @@ package settings
 import (
 	"time"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -27,31 +27,31 @@ func (h HealthyWait) validate() (err error) {
 // unset field of the receiver settings object.
 func (h *HealthyWait) copy() (copied HealthyWait) {
 	return HealthyWait{
-		Initial:  gosettings.CopyPointer(h.Initial),
-		Addition: gosettings.CopyPointer(h.Addition),
+		Initial:  helpers.CopyPointer(h.Initial),
+		Addition: helpers.CopyPointer(h.Addition),
 	}
 }

 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (h *HealthyWait) mergeWith(other HealthyWait) {
-	h.Initial = gosettings.MergeWithPointer(h.Initial, other.Initial)
-	h.Addition = gosettings.MergeWithPointer(h.Addition, other.Addition)
+	h.Initial = helpers.MergeWithPointer(h.Initial, other.Initial)
+	h.Addition = helpers.MergeWithPointer(h.Addition, other.Addition)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (h *HealthyWait) overrideWith(other HealthyWait) {
-	h.Initial = gosettings.OverrideWithPointer(h.Initial, other.Initial)
-	h.Addition = gosettings.OverrideWithPointer(h.Addition, other.Addition)
+	h.Initial = helpers.OverrideWithPointer(h.Initial, other.Initial)
+	h.Addition = helpers.OverrideWithPointer(h.Addition, other.Addition)
 }

 func (h *HealthyWait) setDefaults() {
 	const initialDurationDefault = 6 * time.Second
 	const additionDurationDefault = 5 * time.Second
-	h.Initial = gosettings.DefaultPointer(h.Initial, initialDurationDefault)
-	h.Addition = gosettings.DefaultPointer(h.Addition, additionDurationDefault)
+	h.Initial = helpers.DefaultPointer(h.Initial, initialDurationDefault)
+	h.Addition = helpers.DefaultPointer(h.Addition, additionDurationDefault)
 }

 func (h HealthyWait) String() string {
--- a/internal/configuration/settings/helpers/belong.go
+++ b/internal/configuration/settings/helpers/belong.go
@@ -1,6 +1,12 @@
 package helpers

-func IsOneOf[T comparable](value T, choices ...T) (ok bool) {
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+func IsOneOf(value string, choices ...string) (ok bool) {
 	for _, choice := range choices {
 		if value == choice {
 			return true
@@ -8,3 +14,39 @@ func IsOneOf[T comparable](value T, choices ...T) (ok bool) {
 	}
 	return false
 }
+
+var (
+	ErrNoChoice      = errors.New("one or more values is set but there is no possible value available")
+	ErrValueNotOneOf = errors.New("value is not one of the possible choices")
+)
+
+func AreAllOneOf(values, choices []string) (err error) {
+	if len(values) > 0 && len(choices) == 0 {
+		return fmt.Errorf("%w", ErrNoChoice)
+	}
+
+	set := make(map[string]struct{}, len(choices))
+	for _, choice := range choices {
+		choice = strings.ToLower(choice)
+		set[choice] = struct{}{}
+	}
+
+	for _, value := range values {
+		_, ok := set[value]
+		if !ok {
+			return fmt.Errorf("%w: value %q, choices available are %s",
+				ErrValueNotOneOf, value, strings.Join(choices, ", "))
+		}
+	}
+
+	return nil
+}
+
+func Uint16IsOneOf(port uint16, choices []uint16) (ok bool) {
+	for _, choice := range choices {
+		if port == choice {
+			return true
+		}
+	}
+	return false
+}
--- a/internal/configuration/settings/helpers/copy.go
+++ b/internal/configuration/settings/helpers/copy.go
@@ -0,0 +1,20 @@
+package helpers
+
+import (
+	"net/netip"
+
+	"golang.org/x/exp/slices"
+)
+
+func CopyPointer[T any](original *T) (copied *T) {
+	if original == nil {
+		return nil
+	}
+	copied = new(T)
+	*copied = *original
+	return copied
+}
+
+func CopySlice[T string | uint16 | netip.Addr | netip.Prefix](original []T) (copied []T) {
+	return slices.Clone(original)
+}
--- a/internal/configuration/settings/helpers/default.go
+++ b/internal/configuration/settings/helpers/default.go
@@ -0,0 +1,39 @@
+package helpers
+
+import (
+	"net/netip"
+)
+
+func DefaultPointer[T any](existing *T, defaultValue T) (
+	result *T) {
+	if existing != nil {
+		return existing
+	}
+	result = new(T)
+	*result = defaultValue
+	return result
+}
+
+func DefaultString(existing string, defaultValue string) (
+	result string) {
+	if existing != "" {
+		return existing
+	}
+	return defaultValue
+}
+
+func DefaultNumber[T Number](existing T, defaultValue T) ( //nolint:ireturn
+	result T) {
+	if existing != 0 {
+		return existing
+	}
+	return defaultValue
+}
+
+func DefaultIP(existing netip.Addr, defaultValue netip.Addr) (
+	result netip.Addr) {
+	if existing.IsValid() {
+		return existing
+	}
+	return defaultValue
+}
--- a/internal/configuration/settings/helpers/files.go
+++ b/internal/configuration/settings/helpers/files.go
@@ -0,0 +1,31 @@
+package helpers
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+var (
+	ErrFileDoesNotExist = errors.New("file does not exist")
+	ErrFileRead         = errors.New("cannot read file")
+	ErrFileClose        = errors.New("cannot close file")
+)
+
+func FileExists(path string) (err error) {
+	path = filepath.Clean(path)
+
+	f, err := os.Open(path)
+	if errors.Is(err, os.ErrNotExist) {
+		return fmt.Errorf("%w: %s", ErrFileDoesNotExist, path)
+	} else if err != nil {
+		return fmt.Errorf("%w: %s", ErrFileRead, err)
+	}
+
+	if err := f.Close(); err != nil {
+		return fmt.Errorf("%w: %s", ErrFileClose, err)
+	}
+
+	return nil
+}
--- a/internal/configuration/settings/helpers/generics.go
+++ b/internal/configuration/settings/helpers/generics.go
@@ -0,0 +1,10 @@
+package helpers
+
+import "time"
+
+type Number interface {
+	uint8 | uint16 | uint32 | uint64 | uint |
+		int8 | int16 | int32 | int64 | int |
+		float32 | float64 |
+		time.Duration
+}
--- a/internal/configuration/settings/helpers/merge.go
+++ b/internal/configuration/settings/helpers/merge.go
@@ -0,0 +1,69 @@
+package helpers
+
+import (
+	"net/http"
+	"net/netip"
+)
+
+func MergeWithPointer[T any](existing, other *T) (result *T) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = new(T)
+	*result = *other
+	return result
+}
+
+func MergeWithString(existing, other string) (result string) {
+	if existing != "" {
+		return existing
+	}
+	return other
+}
+
+func MergeWithNumber[T Number](existing, other T) (result T) { //nolint:ireturn
+	if existing != 0 {
+		return existing
+	}
+	return other
+}
+
+func MergeWithIP(existing, other netip.Addr) (result netip.Addr) {
+	if existing.IsValid() {
+		return existing
+	}
+	return other
+}
+
+func MergeWithHTTPHandler(existing, other http.Handler) (result http.Handler) {
+	if existing != nil {
+		return existing
+	}
+	return other
+}
+
+func MergeSlices[T comparable](a, b []T) (result []T) {
+	if a == nil && b == nil {
+		return nil
+	}
+
+	seen := make(map[T]struct{}, len(a)+len(b))
+	result = make([]T, 0, len(a)+len(b))
+	for _, s := range a {
+		if _, ok := seen[s]; ok {
+			continue // duplicate
+		}
+		result = append(result, s)
+		seen[s] = struct{}{}
+	}
+	for _, s := range b {
+		if _, ok := seen[s]; ok {
+			continue // duplicate
+		}
+		result = append(result, s)
+		seen[s] = struct{}{}
+	}
+	return result
+}
--- a/internal/configuration/settings/helpers/messages.go
+++ b/internal/configuration/settings/helpers/messages.go
@@ -0,0 +1,29 @@
+package helpers
+
+import (
+	"fmt"
+	"strings"
+)
+
+func ChoicesOrString(choices []string) string {
+	return strings.Join(
+		choices[:len(choices)-1], ", ") +
+		" or " + choices[len(choices)-1]
+}
+
+func PortChoicesOrString(ports []uint16) (s string) {
+	switch len(ports) {
+	case 0:
+		return "there is no allowed port"
+	case 1:
+		return "allowed port is " + fmt.Sprint(ports[0])
+	}
+
+	s = "allowed ports are "
+	portStrings := make([]string, len(ports))
+	for i := range ports {
+		portStrings[i] = fmt.Sprint(ports[i])
+	}
+	s += ChoicesOrString(portStrings)
+	return s
+}
--- a/internal/configuration/settings/helpers/obfuscate.go
+++ b/internal/configuration/settings/helpers/obfuscate.go
@@ -0,0 +1,25 @@
+package helpers
+
+func ObfuscateWireguardKey(fullKey string) (obfuscatedKey string) {
+	const minKeyLength = 10
+	if len(fullKey) < minKeyLength {
+		return "(too short)"
+	}
+
+	lastIndex := len(fullKey) - 1
+	return fullKey[0:2] + "..." + fullKey[lastIndex-2:]
+}
+
+func ObfuscatePassword(password string) (obfuscatedPassword string) {
+	if password != "" {
+		return "[set]"
+	}
+	return "[not set]"
+}
+
+func ObfuscateData(data string) (obfuscated string) {
+	if data != "" {
+		return "[set]"
+	}
+	return "[not set]"
+}
--- a/internal/configuration/settings/helpers/override.go
+++ b/internal/configuration/settings/helpers/override.go
@@ -0,0 +1,52 @@
+package helpers
+
+import (
+	"net/http"
+	"net/netip"
+)
+
+func OverrideWithPointer[T any](existing, other *T) (result *T) {
+	if other == nil {
+		return existing
+	}
+	result = new(T)
+	*result = *other
+	return result
+}
+
+func OverrideWithString(existing, other string) (result string) {
+	if other == "" {
+		return existing
+	}
+	return other
+}
+
+func OverrideWithNumber[T Number](existing, other T) (result T) { //nolint:ireturn
+	if other == 0 {
+		return existing
+	}
+	return other
+}
+
+func OverrideWithIP(existing, other netip.Addr) (result netip.Addr) {
+	if !other.IsValid() {
+		return existing
+	}
+	return other
+}
+
+func OverrideWithHTTPHandler(existing, other http.Handler) (result http.Handler) {
+	if other != nil {
+		return other
+	}
+	return existing
+}
+
+func OverrideWithSlice[T any](existing, other []T) (result []T) {
+	if other == nil {
+		return existing
+	}
+	result = make([]T, len(other))
+	copy(result, other)
+	return result
+}
--- a/internal/configuration/settings/helpers/string.go
+++ b/internal/configuration/settings/helpers/string.go
@@ -1,5 +1,12 @@
 package helpers

+func BoolPtrToYesNo(b *bool) string {
+	if *b {
+		return "yes"
+	}
+	return "no"
+}
+
 func TCPPtrToString(tcp *bool) string {
 	if *tcp {
 		return "TCP"
--- a/internal/configuration/settings/httpproxy.go
+++ b/internal/configuration/settings/httpproxy.go
@@ -5,7 +5,7 @@ import (
 	"os"
 	"time"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 	"github.com/qdm12/govalid/address"
 )
@@ -46,7 +46,7 @@ func (h HTTPProxy) validate() (err error) {
 	// Do not validate user and password

 	uid := os.Getuid()
-	err = address.Validate(h.ListeningAddress, address.OptionListening(uid))
+	_, err = address.Validate(h.ListeningAddress, address.OptionListening(uid))
 	if err != nil {
 		return fmt.Errorf("%w: %s", ErrServerAddressNotValid, h.ListeningAddress)
 	}
@@ -56,12 +56,12 @@ func (h HTTPProxy) validate() (err error) {

 func (h *HTTPProxy) copy() (copied HTTPProxy) {
 	return HTTPProxy{
-		User:              gosettings.CopyPointer(h.User),
-		Password:          gosettings.CopyPointer(h.Password),
+		User:              helpers.CopyPointer(h.User),
+		Password:          helpers.CopyPointer(h.Password),
 		ListeningAddress:  h.ListeningAddress,
-		Enabled:           gosettings.CopyPointer(h.Enabled),
-		Stealth:           gosettings.CopyPointer(h.Stealth),
-		Log:               gosettings.CopyPointer(h.Log),
+		Enabled:           helpers.CopyPointer(h.Enabled),
+		Stealth:           helpers.CopyPointer(h.Stealth),
+		Log:               helpers.CopyPointer(h.Log),
 		ReadHeaderTimeout: h.ReadHeaderTimeout,
 		ReadTimeout:       h.ReadTimeout,
 	}
@@ -70,41 +70,41 @@ func (h *HTTPProxy) copy() (copied HTTPProxy) {
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (h *HTTPProxy) mergeWith(other HTTPProxy) {
-	h.User = gosettings.MergeWithPointer(h.User, other.User)
-	h.Password = gosettings.MergeWithPointer(h.Password, other.Password)
-	h.ListeningAddress = gosettings.MergeWithString(h.ListeningAddress, other.ListeningAddress)
-	h.Enabled = gosettings.MergeWithPointer(h.Enabled, other.Enabled)
-	h.Stealth = gosettings.MergeWithPointer(h.Stealth, other.Stealth)
-	h.Log = gosettings.MergeWithPointer(h.Log, other.Log)
-	h.ReadHeaderTimeout = gosettings.MergeWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = gosettings.MergeWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.User = helpers.MergeWithPointer(h.User, other.User)
+	h.Password = helpers.MergeWithPointer(h.Password, other.Password)
+	h.ListeningAddress = helpers.MergeWithString(h.ListeningAddress, other.ListeningAddress)
+	h.Enabled = helpers.MergeWithPointer(h.Enabled, other.Enabled)
+	h.Stealth = helpers.MergeWithPointer(h.Stealth, other.Stealth)
+	h.Log = helpers.MergeWithPointer(h.Log, other.Log)
+	h.ReadHeaderTimeout = helpers.MergeWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.MergeWithNumber(h.ReadTimeout, other.ReadTimeout)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (h *HTTPProxy) overrideWith(other HTTPProxy) {
-	h.User = gosettings.OverrideWithPointer(h.User, other.User)
-	h.Password = gosettings.OverrideWithPointer(h.Password, other.Password)
-	h.ListeningAddress = gosettings.OverrideWithString(h.ListeningAddress, other.ListeningAddress)
-	h.Enabled = gosettings.OverrideWithPointer(h.Enabled, other.Enabled)
-	h.Stealth = gosettings.OverrideWithPointer(h.Stealth, other.Stealth)
-	h.Log = gosettings.OverrideWithPointer(h.Log, other.Log)
-	h.ReadHeaderTimeout = gosettings.OverrideWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = gosettings.OverrideWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.User = helpers.OverrideWithPointer(h.User, other.User)
+	h.Password = helpers.OverrideWithPointer(h.Password, other.Password)
+	h.ListeningAddress = helpers.OverrideWithString(h.ListeningAddress, other.ListeningAddress)
+	h.Enabled = helpers.OverrideWithPointer(h.Enabled, other.Enabled)
+	h.Stealth = helpers.OverrideWithPointer(h.Stealth, other.Stealth)
+	h.Log = helpers.OverrideWithPointer(h.Log, other.Log)
+	h.ReadHeaderTimeout = helpers.OverrideWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.OverrideWithNumber(h.ReadTimeout, other.ReadTimeout)
 }

 func (h *HTTPProxy) setDefaults() {
-	h.User = gosettings.DefaultPointer(h.User, "")
-	h.Password = gosettings.DefaultPointer(h.Password, "")
-	h.ListeningAddress = gosettings.DefaultString(h.ListeningAddress, ":8888")
-	h.Enabled = gosettings.DefaultPointer(h.Enabled, false)
-	h.Stealth = gosettings.DefaultPointer(h.Stealth, false)
-	h.Log = gosettings.DefaultPointer(h.Log, false)
+	h.User = helpers.DefaultPointer(h.User, "")
+	h.Password = helpers.DefaultPointer(h.Password, "")
+	h.ListeningAddress = helpers.DefaultString(h.ListeningAddress, ":8888")
+	h.Enabled = helpers.DefaultPointer(h.Enabled, false)
+	h.Stealth = helpers.DefaultPointer(h.Stealth, false)
+	h.Log = helpers.DefaultPointer(h.Log, false)
 	const defaultReadHeaderTimeout = time.Second
-	h.ReadHeaderTimeout = gosettings.DefaultNumber(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
+	h.ReadHeaderTimeout = helpers.DefaultNumber(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
 	const defaultReadTimeout = 3 * time.Second
-	h.ReadTimeout = gosettings.DefaultNumber(h.ReadTimeout, defaultReadTimeout)
+	h.ReadTimeout = helpers.DefaultNumber(h.ReadTimeout, defaultReadTimeout)
 }

 func (h HTTPProxy) String() string {
@@ -113,16 +113,16 @@ func (h HTTPProxy) String() string {

 func (h HTTPProxy) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("HTTP proxy settings:")
-	node.Appendf("Enabled: %s", gosettings.BoolToYesNo(h.Enabled))
+	node.Appendf("Enabled: %s", helpers.BoolPtrToYesNo(h.Enabled))
 	if !*h.Enabled {
 		return node
 	}

 	node.Appendf("Listening address: %s", h.ListeningAddress)
 	node.Appendf("User: %s", *h.User)
-	node.Appendf("Password: %s", gosettings.ObfuscateKey(*h.Password))
-	node.Appendf("Stealth mode: %s", gosettings.BoolToYesNo(h.Stealth))
-	node.Appendf("Log: %s", gosettings.BoolToYesNo(h.Log))
+	node.Appendf("Password: %s", helpers.ObfuscatePassword(*h.Password))
+	node.Appendf("Stealth mode: %s", helpers.BoolPtrToYesNo(h.Stealth))
+	node.Appendf("Log: %s", helpers.BoolPtrToYesNo(h.Log))
 	node.Appendf("Read header timeout: %s", h.ReadHeaderTimeout)
 	node.Appendf("Read timeout: %s", h.ReadTimeout)

--- a/internal/configuration/settings/log.go
+++ b/internal/configuration/settings/log.go
@@ -1,7 +1,7 @@
 package settings

 import (
-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 	"github.com/qdm12/log"
 )
@@ -19,25 +19,25 @@ func (l Log) validate() (err error) {

 func (l *Log) copy() (copied Log) {
 	return Log{
-		Level: gosettings.CopyPointer(l.Level),
+		Level: helpers.CopyPointer(l.Level),
 	}
 }

 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (l *Log) mergeWith(other Log) {
-	l.Level = gosettings.MergeWithPointer(l.Level, other.Level)
+	l.Level = helpers.MergeWithPointer(l.Level, other.Level)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (l *Log) overrideWith(other Log) {
-	l.Level = gosettings.OverrideWithPointer(l.Level, other.Level)
+	l.Level = helpers.OverrideWithPointer(l.Level, other.Level)
 }

 func (l *Log) setDefaults() {
-	l.Level = gosettings.DefaultPointer(l.Level, log.LevelInfo)
+	l.Level = helpers.DefaultPointer(l.Level, log.LevelInfo)
 }

 func (l Log) String() string {
--- a/internal/configuration/settings/nordvpn_retro.go
+++ b/internal/configuration/settings/nordvpn_retro.go
@@ -1,42 +0,0 @@
-package settings
-
-// Retro-compatibility because SERVER_REGIONS changed to SERVER_COUNTRIES
-// and SERVER_REGIONS is now the continent field for servers.
-// TODO v4 remove.
-func nordvpnRetroRegion(selection ServerSelection, validRegions, validCountries []string) (
-	updatedSelection ServerSelection) {
-	validRegionsMap := stringSliceToMap(validRegions)
-	validCountriesMap := stringSliceToMap(validCountries)
-
-	updatedSelection = selection.copy()
-	updatedSelection.Regions = make([]string, 0, len(selection.Regions))
-	for _, region := range selection.Regions {
-		_, isValid := validRegionsMap[region]
-		if isValid {
-			updatedSelection.Regions = append(updatedSelection.Regions, region)
-			continue
-		}
-
-		_, isValid = validCountriesMap[region]
-		if !isValid {
-			// Region is not valid for the country or region
-			// just leave it to the validation to fail it later
-			continue
-		}
-
-		// Region is not valid for a region, but is a valid country
-		// Handle retro-compatibility and transfer the value to the
-		// country field.
-		updatedSelection.Countries = append(updatedSelection.Countries, region)
-	}
-
-	return updatedSelection
-}
-
-func stringSliceToMap(slice []string) (m map[string]struct{}) {
-	m = make(map[string]struct{}, len(slice))
-	for _, s := range slice {
-		m[s] = struct{}{}
-	}
-	return m
-}
--- a/internal/configuration/settings/openvpn.go
+++ b/internal/configuration/settings/openvpn.go
@@ -4,93 +4,94 @@ import (
 	"encoding/base64"
 	"fmt"
 	"regexp"
+	"strings"

+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/openvpn"
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/openvpn/extract"
 	"github.com/qdm12/gluetun/internal/provider/privateinternetaccess/presets"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 )

 // OpenVPN contains settings to configure the OpenVPN client.
 type OpenVPN struct {
 	// Version is the OpenVPN version to run.
-	// It can only be "2.5" or "2.6".
-	Version string `json:"version"`
+	// It can only be "2.4" or "2.5".
+	Version string
 	// User is the OpenVPN authentication username.
 	// It cannot be nil in the internal state if OpenVPN is used.
 	// It is usually required but in some cases can be the empty string
 	// to indicate no user+password authentication is needed.
-	User *string `json:"user"`
+	User *string
 	// Password is the OpenVPN authentication password.
 	// It cannot be nil in the internal state if OpenVPN is used.
 	// It is usually required but in some cases can be the empty string
 	// to indicate no user+password authentication is needed.
-	Password *string `json:"password"`
+	Password *string
 	// ConfFile is a custom OpenVPN configuration file path.
 	// It can be set to the empty string for it to be ignored.
 	// It cannot be nil in the internal state.
-	ConfFile *string `json:"config_file_path"`
+	ConfFile *string
 	// Ciphers is a list of ciphers to use for OpenVPN,
 	// different from the ones specified by the VPN
 	// service provider configuration files.
-	Ciphers []string `json:"ciphers"`
+	Ciphers []string
 	// Auth is an auth algorithm to use in OpenVPN instead
 	// of the one specified by the VPN service provider.
 	// It cannot be nil in the internal state.
 	// It is ignored if it is set to the empty string.
-	Auth *string `json:"auth"`
+	Auth *string
 	// Cert is the base64 encoded DER of an OpenVPN certificate for the <cert> block.
 	// This is notably used by Cyberghost and VPN secure.
 	// It can be set to the empty string to be ignored.
 	// It cannot be nil in the internal state.
-	Cert *string `json:"cert"`
+	Cert *string
 	// Key is the base64 encoded DER of an OpenVPN key.
 	// This is used by Cyberghost and VPN Unlimited.
 	// It can be set to the empty string to be ignored.
 	// It cannot be nil in the internal state.
-	Key *string `json:"key"`
+	Key *string
 	// EncryptedKey is the base64 encoded DER of an encrypted key for OpenVPN.
 	// It is used by VPN secure.
 	// It defaults to the empty string meaning it is not
 	// to be used. KeyPassphrase must be set if this one is set.
-	EncryptedKey *string `json:"encrypted_key"`
+	EncryptedKey *string
 	// KeyPassphrase is the key passphrase to be used by OpenVPN
 	// to decrypt the EncryptedPrivateKey. It defaults to the
 	// empty string and must be set if EncryptedPrivateKey is set.
-	KeyPassphrase *string `json:"key_passphrase"`
+	KeyPassphrase *string
 	// PIAEncPreset is the encryption preset for
 	// Private Internet Access. It can be set to an
 	// empty string for other providers.
-	PIAEncPreset *string `json:"pia_encryption_preset"`
+	PIAEncPreset *string
 	// MSSFix is the value (1 to 10000) to set for the
 	// mssfix option for OpenVPN. It is ignored if set to 0.
 	// It cannot be nil in the internal state.
-	MSSFix *uint16 `json:"mssfix"`
+	MSSFix *uint16
 	// Interface is the OpenVPN device interface name.
 	// It cannot be an empty string in the internal state.
-	Interface string `json:"interface"`
+	Interface string
 	// ProcessUser is the OpenVPN process OS username
 	// to use. It cannot be empty in the internal state.
 	// It defaults to 'root'.
-	ProcessUser string `json:"process_user"`
+	ProcessUser string
 	// Verbosity is the OpenVPN verbosity level from 0 to 6.
 	// It cannot be nil in the internal state.
-	Verbosity *int `json:"verbosity"`
+	Verbosity *int
 	// Flags is a slice of additional flags to be passed
 	// to the OpenVPN program.
-	Flags []string `json:"flags"`
+	Flags []string
 }

 var ivpnAccountID = regexp.MustCompile(`^(i|ivpn)\-[a-zA-Z0-9]{4}\-[a-zA-Z0-9]{4}\-[a-zA-Z0-9]{4}$`)

 func (o OpenVPN) validate(vpnProvider string) (err error) {
 	// Validate version
-	validVersions := []string{openvpn.Openvpn25, openvpn.Openvpn26}
-	if err = validate.IsOneOf(o.Version, validVersions...); err != nil {
-		return fmt.Errorf("%w: %w", ErrOpenVPNVersionIsNotValid, err)
+	validVersions := []string{openvpn.Openvpn24, openvpn.Openvpn25}
+	if !helpers.IsOneOf(o.Version, validVersions...) {
+		return fmt.Errorf("%w: %q can only be one of %s",
+			ErrOpenVPNVersionIsNotValid, o.Version, strings.Join(validVersions, ", "))
 	}

 	isCustom := vpnProvider == providers.Custom
@@ -162,7 +163,7 @@ func validateOpenVPNConfigFilepath(isCustom bool,
 		return fmt.Errorf("%w", ErrFilepathMissing)
 	}

-	err = validate.FileExists(confFile)
+	err = helpers.FileExists(confFile)
 	if err != nil {
 		return err
 	}
@@ -243,92 +244,92 @@ func validateOpenVPNEncryptedKey(vpnProvider,
 func (o *OpenVPN) copy() (copied OpenVPN) {
 	return OpenVPN{
 		Version:       o.Version,
-		User:          gosettings.CopyPointer(o.User),
-		Password:      gosettings.CopyPointer(o.Password),
-		ConfFile:      gosettings.CopyPointer(o.ConfFile),
-		Ciphers:       gosettings.CopySlice(o.Ciphers),
-		Auth:          gosettings.CopyPointer(o.Auth),
-		Cert:          gosettings.CopyPointer(o.Cert),
-		Key:           gosettings.CopyPointer(o.Key),
-		EncryptedKey:  gosettings.CopyPointer(o.EncryptedKey),
-		KeyPassphrase: gosettings.CopyPointer(o.KeyPassphrase),
-		PIAEncPreset:  gosettings.CopyPointer(o.PIAEncPreset),
-		MSSFix:        gosettings.CopyPointer(o.MSSFix),
+		User:          helpers.CopyPointer(o.User),
+		Password:      helpers.CopyPointer(o.Password),
+		ConfFile:      helpers.CopyPointer(o.ConfFile),
+		Ciphers:       helpers.CopySlice(o.Ciphers),
+		Auth:          helpers.CopyPointer(o.Auth),
+		Cert:          helpers.CopyPointer(o.Cert),
+		Key:           helpers.CopyPointer(o.Key),
+		EncryptedKey:  helpers.CopyPointer(o.EncryptedKey),
+		KeyPassphrase: helpers.CopyPointer(o.KeyPassphrase),
+		PIAEncPreset:  helpers.CopyPointer(o.PIAEncPreset),
+		MSSFix:        helpers.CopyPointer(o.MSSFix),
 		Interface:     o.Interface,
 		ProcessUser:   o.ProcessUser,
-		Verbosity:     gosettings.CopyPointer(o.Verbosity),
-		Flags:         gosettings.CopySlice(o.Flags),
+		Verbosity:     helpers.CopyPointer(o.Verbosity),
+		Flags:         helpers.CopySlice(o.Flags),
 	}
 }

 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (o *OpenVPN) mergeWith(other OpenVPN) {
-	o.Version = gosettings.MergeWithString(o.Version, other.Version)
-	o.User = gosettings.MergeWithPointer(o.User, other.User)
-	o.Password = gosettings.MergeWithPointer(o.Password, other.Password)
-	o.ConfFile = gosettings.MergeWithPointer(o.ConfFile, other.ConfFile)
-	o.Ciphers = gosettings.MergeWithSlice(o.Ciphers, other.Ciphers)
-	o.Auth = gosettings.MergeWithPointer(o.Auth, other.Auth)
-	o.Cert = gosettings.MergeWithPointer(o.Cert, other.Cert)
-	o.Key = gosettings.MergeWithPointer(o.Key, other.Key)
-	o.EncryptedKey = gosettings.MergeWithPointer(o.EncryptedKey, other.EncryptedKey)
-	o.KeyPassphrase = gosettings.MergeWithPointer(o.KeyPassphrase, other.KeyPassphrase)
-	o.PIAEncPreset = gosettings.MergeWithPointer(o.PIAEncPreset, other.PIAEncPreset)
-	o.MSSFix = gosettings.MergeWithPointer(o.MSSFix, other.MSSFix)
-	o.Interface = gosettings.MergeWithString(o.Interface, other.Interface)
-	o.ProcessUser = gosettings.MergeWithString(o.ProcessUser, other.ProcessUser)
-	o.Verbosity = gosettings.MergeWithPointer(o.Verbosity, other.Verbosity)
-	o.Flags = gosettings.MergeWithSlice(o.Flags, other.Flags)
+	o.Version = helpers.MergeWithString(o.Version, other.Version)
+	o.User = helpers.MergeWithPointer(o.User, other.User)
+	o.Password = helpers.MergeWithPointer(o.Password, other.Password)
+	o.ConfFile = helpers.MergeWithPointer(o.ConfFile, other.ConfFile)
+	o.Ciphers = helpers.MergeSlices(o.Ciphers, other.Ciphers)
+	o.Auth = helpers.MergeWithPointer(o.Auth, other.Auth)
+	o.Cert = helpers.MergeWithPointer(o.Cert, other.Cert)
+	o.Key = helpers.MergeWithPointer(o.Key, other.Key)
+	o.EncryptedKey = helpers.MergeWithPointer(o.EncryptedKey, other.EncryptedKey)
+	o.KeyPassphrase = helpers.MergeWithPointer(o.KeyPassphrase, other.KeyPassphrase)
+	o.PIAEncPreset = helpers.MergeWithPointer(o.PIAEncPreset, other.PIAEncPreset)
+	o.MSSFix = helpers.MergeWithPointer(o.MSSFix, other.MSSFix)
+	o.Interface = helpers.MergeWithString(o.Interface, other.Interface)
+	o.ProcessUser = helpers.MergeWithString(o.ProcessUser, other.ProcessUser)
+	o.Verbosity = helpers.MergeWithPointer(o.Verbosity, other.Verbosity)
+	o.Flags = helpers.MergeSlices(o.Flags, other.Flags)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (o *OpenVPN) overrideWith(other OpenVPN) {
-	o.Version = gosettings.OverrideWithString(o.Version, other.Version)
-	o.User = gosettings.OverrideWithPointer(o.User, other.User)
-	o.Password = gosettings.OverrideWithPointer(o.Password, other.Password)
-	o.ConfFile = gosettings.OverrideWithPointer(o.ConfFile, other.ConfFile)
-	o.Ciphers = gosettings.OverrideWithSlice(o.Ciphers, other.Ciphers)
-	o.Auth = gosettings.OverrideWithPointer(o.Auth, other.Auth)
-	o.Cert = gosettings.OverrideWithPointer(o.Cert, other.Cert)
-	o.Key = gosettings.OverrideWithPointer(o.Key, other.Key)
-	o.EncryptedKey = gosettings.OverrideWithPointer(o.EncryptedKey, other.EncryptedKey)
-	o.KeyPassphrase = gosettings.OverrideWithPointer(o.KeyPassphrase, other.KeyPassphrase)
-	o.PIAEncPreset = gosettings.OverrideWithPointer(o.PIAEncPreset, other.PIAEncPreset)
-	o.MSSFix = gosettings.OverrideWithPointer(o.MSSFix, other.MSSFix)
-	o.Interface = gosettings.OverrideWithString(o.Interface, other.Interface)
-	o.ProcessUser = gosettings.OverrideWithString(o.ProcessUser, other.ProcessUser)
-	o.Verbosity = gosettings.OverrideWithPointer(o.Verbosity, other.Verbosity)
-	o.Flags = gosettings.OverrideWithSlice(o.Flags, other.Flags)
+	o.Version = helpers.OverrideWithString(o.Version, other.Version)
+	o.User = helpers.OverrideWithPointer(o.User, other.User)
+	o.Password = helpers.OverrideWithPointer(o.Password, other.Password)
+	o.ConfFile = helpers.OverrideWithPointer(o.ConfFile, other.ConfFile)
+	o.Ciphers = helpers.OverrideWithSlice(o.Ciphers, other.Ciphers)
+	o.Auth = helpers.OverrideWithPointer(o.Auth, other.Auth)
+	o.Cert = helpers.OverrideWithPointer(o.Cert, other.Cert)
+	o.Key = helpers.OverrideWithPointer(o.Key, other.Key)
+	o.EncryptedKey = helpers.OverrideWithPointer(o.EncryptedKey, other.EncryptedKey)
+	o.KeyPassphrase = helpers.OverrideWithPointer(o.KeyPassphrase, other.KeyPassphrase)
+	o.PIAEncPreset = helpers.OverrideWithPointer(o.PIAEncPreset, other.PIAEncPreset)
+	o.MSSFix = helpers.OverrideWithPointer(o.MSSFix, other.MSSFix)
+	o.Interface = helpers.OverrideWithString(o.Interface, other.Interface)
+	o.ProcessUser = helpers.OverrideWithString(o.ProcessUser, other.ProcessUser)
+	o.Verbosity = helpers.OverrideWithPointer(o.Verbosity, other.Verbosity)
+	o.Flags = helpers.OverrideWithSlice(o.Flags, other.Flags)
 }

 func (o *OpenVPN) setDefaults(vpnProvider string) {
-	o.Version = gosettings.DefaultString(o.Version, openvpn.Openvpn25)
-	o.User = gosettings.DefaultPointer(o.User, "")
+	o.Version = helpers.DefaultString(o.Version, openvpn.Openvpn25)
+	o.User = helpers.DefaultPointer(o.User, "")
 	if vpnProvider == providers.Mullvad {
-		o.Password = gosettings.DefaultPointer(o.Password, "m")
+		o.Password = helpers.DefaultPointer(o.Password, "m")
 	} else {
-		o.Password = gosettings.DefaultPointer(o.Password, "")
+		o.Password = helpers.DefaultPointer(o.Password, "")
 	}

-	o.ConfFile = gosettings.DefaultPointer(o.ConfFile, "")
-	o.Auth = gosettings.DefaultPointer(o.Auth, "")
-	o.Cert = gosettings.DefaultPointer(o.Cert, "")
-	o.Key = gosettings.DefaultPointer(o.Key, "")
-	o.EncryptedKey = gosettings.DefaultPointer(o.EncryptedKey, "")
-	o.KeyPassphrase = gosettings.DefaultPointer(o.KeyPassphrase, "")
+	o.ConfFile = helpers.DefaultPointer(o.ConfFile, "")
+	o.Auth = helpers.DefaultPointer(o.Auth, "")
+	o.Cert = helpers.DefaultPointer(o.Cert, "")
+	o.Key = helpers.DefaultPointer(o.Key, "")
+	o.EncryptedKey = helpers.DefaultPointer(o.EncryptedKey, "")
+	o.KeyPassphrase = helpers.DefaultPointer(o.KeyPassphrase, "")

 	var defaultEncPreset string
 	if vpnProvider == providers.PrivateInternetAccess {
 		defaultEncPreset = presets.Strong
 	}
-	o.PIAEncPreset = gosettings.DefaultPointer(o.PIAEncPreset, defaultEncPreset)
-	o.MSSFix = gosettings.DefaultPointer(o.MSSFix, 0)
-	o.Interface = gosettings.DefaultString(o.Interface, "tun0")
-	o.ProcessUser = gosettings.DefaultString(o.ProcessUser, "root")
-	o.Verbosity = gosettings.DefaultPointer(o.Verbosity, 1)
+	o.PIAEncPreset = helpers.DefaultPointer(o.PIAEncPreset, defaultEncPreset)
+	o.MSSFix = helpers.DefaultPointer(o.MSSFix, 0)
+	o.Interface = helpers.DefaultString(o.Interface, "tun0")
+	o.ProcessUser = helpers.DefaultString(o.ProcessUser, "root")
+	o.Verbosity = helpers.DefaultPointer(o.Verbosity, 1)
 }

 func (o OpenVPN) String() string {
@@ -338,8 +339,8 @@ func (o OpenVPN) String() string {
 func (o OpenVPN) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("OpenVPN settings:")
 	node.Appendf("OpenVPN version: %s", o.Version)
-	node.Appendf("User: %s", gosettings.ObfuscateKey(*o.User))
-	node.Appendf("Password: %s", gosettings.ObfuscateKey(*o.Password))
+	node.Appendf("User: %s", helpers.ObfuscatePassword(*o.User))
+	node.Appendf("Password: %s", helpers.ObfuscatePassword(*o.Password))

 	if *o.ConfFile != "" {
 		node.Appendf("Custom configuration file: %s", *o.ConfFile)
@@ -354,16 +355,16 @@ func (o OpenVPN) toLinesNode() (node *gotree.Node) {
 	}

 	if *o.Cert != "" {
-		node.Appendf("Client crt: %s", gosettings.ObfuscateKey(*o.Cert))
+		node.Appendf("Client crt: %s", helpers.ObfuscateData(*o.Cert))
 	}

 	if *o.Key != "" {
-		node.Appendf("Client key: %s", gosettings.ObfuscateKey(*o.Key))
+		node.Appendf("Client key: %s", helpers.ObfuscateData(*o.Key))
 	}

 	if *o.EncryptedKey != "" {
 		node.Appendf("Encrypted key: %s (key passhrapse %s)",
-			gosettings.ObfuscateKey(*o.EncryptedKey), gosettings.ObfuscateKey(*o.KeyPassphrase))
+			helpers.ObfuscateData(*o.EncryptedKey), helpers.ObfuscatePassword(*o.KeyPassphrase))
 	}

 	if *o.PIAEncPreset != "" {
--- a/internal/configuration/settings/openvpnselection.go
+++ b/internal/configuration/settings/openvpnselection.go
@@ -6,8 +6,6 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/provider/privateinternetaccess/presets"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 )

@@ -16,25 +14,25 @@ type OpenVPNSelection struct {
 	// It can be set to an empty string to indicate to
 	// NOT use a custom configuration file.
 	// It cannot be nil in the internal state.
-	ConfFile *string `json:"config_file_path"`
+	ConfFile *string
 	// TCP is true if the OpenVPN protocol is TCP,
 	// and false for UDP.
 	// It cannot be nil in the internal state.
-	TCP *bool `json:"tcp"`
+	TCP *bool
 	// CustomPort is the OpenVPN server endpoint port.
 	// It can be set to 0 to indicate no custom port should
 	// be used. It cannot be nil in the internal state.
-	CustomPort *uint16 `json:"custom_port"`
+	CustomPort *uint16 // HideMyAss, Mullvad, PIA, ProtonVPN, WeVPN, Windscribe
 	// PIAEncPreset is the encryption preset for
 	// Private Internet Access. It can be set to an
 	// empty string for other providers.
-	PIAEncPreset *string `json:"pia_encryption_preset"`
+	PIAEncPreset *string
 }

 func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 	// Validate ConfFile
 	if confFile := *o.ConfFile; confFile != "" {
-		err := validate.FileExists(confFile)
+		err := helpers.FileExists(confFile)
 		if err != nil {
 			return fmt.Errorf("configuration file: %w", err)
 		}
@@ -101,14 +99,14 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 				allowedUDP = []uint16{53, 80, 123, 443, 1194, 54783}
 			}

-			allowedPorts := allowedUDP
-			if *o.TCP {
-				allowedPorts = allowedTCP
-			}
-			err = validate.IsOneOf(*o.CustomPort, allowedPorts...)
-			if err != nil {
-				return fmt.Errorf("%w: for VPN service provider %s: %w",
-					ErrOpenVPNCustomPortNotAllowed, vpnProvider, err)
+			if *o.TCP && !helpers.Uint16IsOneOf(*o.CustomPort, allowedTCP) {
+				return fmt.Errorf("%w: %d for VPN service provider %s; %s",
+					ErrOpenVPNCustomPortNotAllowed, o.CustomPort, vpnProvider,
+					helpers.PortChoicesOrString(allowedTCP))
+			} else if !*o.TCP && !helpers.Uint16IsOneOf(*o.CustomPort, allowedUDP) {
+				return fmt.Errorf("%w: %d for VPN service provider %s; %s",
+					ErrOpenVPNCustomPortNotAllowed, o.CustomPort, vpnProvider,
+					helpers.PortChoicesOrString(allowedUDP))
 			}
 		}
 	}
@@ -120,8 +118,10 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 			presets.Normal,
 			presets.Strong,
 		}
-		if err = validate.IsOneOf(*o.PIAEncPreset, validEncryptionPresets...); err != nil {
-			return fmt.Errorf("%w: %w", ErrOpenVPNEncryptionPresetNotValid, err)
+		if !helpers.IsOneOf(*o.PIAEncPreset, validEncryptionPresets...) {
+			return fmt.Errorf("%w: %s; valid presets are %s",
+				ErrOpenVPNEncryptionPresetNotValid, *o.PIAEncPreset,
+				helpers.ChoicesOrString(validEncryptionPresets))
 		}
 	}

@@ -130,37 +130,37 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {

 func (o *OpenVPNSelection) copy() (copied OpenVPNSelection) {
 	return OpenVPNSelection{
-		ConfFile:     gosettings.CopyPointer(o.ConfFile),
-		TCP:          gosettings.CopyPointer(o.TCP),
-		CustomPort:   gosettings.CopyPointer(o.CustomPort),
-		PIAEncPreset: gosettings.CopyPointer(o.PIAEncPreset),
+		ConfFile:     helpers.CopyPointer(o.ConfFile),
+		TCP:          helpers.CopyPointer(o.TCP),
+		CustomPort:   helpers.CopyPointer(o.CustomPort),
+		PIAEncPreset: helpers.CopyPointer(o.PIAEncPreset),
 	}
 }

 func (o *OpenVPNSelection) mergeWith(other OpenVPNSelection) {
-	o.ConfFile = gosettings.MergeWithPointer(o.ConfFile, other.ConfFile)
-	o.TCP = gosettings.MergeWithPointer(o.TCP, other.TCP)
-	o.CustomPort = gosettings.MergeWithPointer(o.CustomPort, other.CustomPort)
-	o.PIAEncPreset = gosettings.MergeWithPointer(o.PIAEncPreset, other.PIAEncPreset)
+	o.ConfFile = helpers.MergeWithPointer(o.ConfFile, other.ConfFile)
+	o.TCP = helpers.MergeWithPointer(o.TCP, other.TCP)
+	o.CustomPort = helpers.MergeWithPointer(o.CustomPort, other.CustomPort)
+	o.PIAEncPreset = helpers.MergeWithPointer(o.PIAEncPreset, other.PIAEncPreset)
 }

 func (o *OpenVPNSelection) overrideWith(other OpenVPNSelection) {
-	o.ConfFile = gosettings.OverrideWithPointer(o.ConfFile, other.ConfFile)
-	o.TCP = gosettings.OverrideWithPointer(o.TCP, other.TCP)
-	o.CustomPort = gosettings.OverrideWithPointer(o.CustomPort, other.CustomPort)
-	o.PIAEncPreset = gosettings.OverrideWithPointer(o.PIAEncPreset, other.PIAEncPreset)
+	o.ConfFile = helpers.OverrideWithPointer(o.ConfFile, other.ConfFile)
+	o.TCP = helpers.OverrideWithPointer(o.TCP, other.TCP)
+	o.CustomPort = helpers.OverrideWithPointer(o.CustomPort, other.CustomPort)
+	o.PIAEncPreset = helpers.OverrideWithPointer(o.PIAEncPreset, other.PIAEncPreset)
 }

 func (o *OpenVPNSelection) setDefaults(vpnProvider string) {
-	o.ConfFile = gosettings.DefaultPointer(o.ConfFile, "")
-	o.TCP = gosettings.DefaultPointer(o.TCP, false)
-	o.CustomPort = gosettings.DefaultPointer(o.CustomPort, 0)
+	o.ConfFile = helpers.DefaultPointer(o.ConfFile, "")
+	o.TCP = helpers.DefaultPointer(o.TCP, false)
+	o.CustomPort = helpers.DefaultPointer(o.CustomPort, 0)

 	var defaultEncPreset string
 	if vpnProvider == providers.PrivateInternetAccess {
 		defaultEncPreset = presets.Strong
 	}
-	o.PIAEncPreset = gosettings.DefaultPointer(o.PIAEncPreset, defaultEncPreset)
+	o.PIAEncPreset = helpers.DefaultPointer(o.PIAEncPreset, defaultEncPreset)
 }

 func (o OpenVPNSelection) String() string {
--- a/internal/configuration/settings/portforward.go
+++ b/internal/configuration/settings/portforward.go
@@ -3,10 +3,10 @@ package settings
 import (
 	"fmt"
 	"path/filepath"
+	"strings"

+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 )

@@ -14,12 +14,12 @@ import (
 type PortForwarding struct {
 	// Enabled is true if port forwarding should be activated.
 	// It cannot be nil for the internal state.
-	Enabled *bool `json:"enabled"`
+	Enabled *bool
 	// Filepath is the port forwarding status file path
 	// to use. It can be the empty string to indicate not
 	// to write to a file. It cannot be nil for the
 	// internal state
-	Filepath *string `json:"status_file_path"`
+	Filepath *string
 }

 func (p PortForwarding) validate(vpnProvider string) (err error) {
@@ -29,8 +29,9 @@ func (p PortForwarding) validate(vpnProvider string) (err error) {

 	// Validate Enabled
 	validProviders := []string{providers.PrivateInternetAccess}
-	if err = validate.IsOneOf(vpnProvider, validProviders...); err != nil {
-		return fmt.Errorf("%w: %w", ErrPortForwardingEnabled, err)
+	if !helpers.IsOneOf(vpnProvider, validProviders...) {
+		return fmt.Errorf("%w: for provider %s, it is only available for %s",
+			ErrPortForwardingEnabled, vpnProvider, strings.Join(validProviders, ", "))
 	}

 	// Validate Filepath
@@ -46,24 +47,24 @@ func (p PortForwarding) validate(vpnProvider string) (err error) {

 func (p *PortForwarding) copy() (copied PortForwarding) {
 	return PortForwarding{
-		Enabled:  gosettings.CopyPointer(p.Enabled),
-		Filepath: gosettings.CopyPointer(p.Filepath),
+		Enabled:  helpers.CopyPointer(p.Enabled),
+		Filepath: helpers.CopyPointer(p.Filepath),
 	}
 }

 func (p *PortForwarding) mergeWith(other PortForwarding) {
-	p.Enabled = gosettings.MergeWithPointer(p.Enabled, other.Enabled)
-	p.Filepath = gosettings.MergeWithPointer(p.Filepath, other.Filepath)
+	p.Enabled = helpers.MergeWithPointer(p.Enabled, other.Enabled)
+	p.Filepath = helpers.MergeWithPointer(p.Filepath, other.Filepath)
 }

 func (p *PortForwarding) overrideWith(other PortForwarding) {
-	p.Enabled = gosettings.OverrideWithPointer(p.Enabled, other.Enabled)
-	p.Filepath = gosettings.OverrideWithPointer(p.Filepath, other.Filepath)
+	p.Enabled = helpers.OverrideWithPointer(p.Enabled, other.Enabled)
+	p.Filepath = helpers.OverrideWithPointer(p.Filepath, other.Filepath)
 }

 func (p *PortForwarding) setDefaults() {
-	p.Enabled = gosettings.DefaultPointer(p.Enabled, false)
-	p.Filepath = gosettings.DefaultPointer(p.Filepath, "/tmp/gluetun/forwarded_port")
+	p.Enabled = helpers.DefaultPointer(p.Enabled, false)
+	p.Filepath = helpers.DefaultPointer(p.Filepath, "/tmp/gluetun/forwarded_port")
 }

 func (p PortForwarding) String() string {
--- a/internal/configuration/settings/provider.go
+++ b/internal/configuration/settings/provider.go
@@ -3,10 +3,9 @@ package settings
 import (
 	"fmt"

+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/constants/vpn"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 )

@@ -14,12 +13,12 @@ import (
 type Provider struct {
 	// Name is the VPN service provider name.
 	// It cannot be nil in the internal state.
-	Name *string `json:"name"`
+	Name *string
 	// ServerSelection is the settings to
 	// select the VPN server.
-	ServerSelection ServerSelection `json:"server_selection"`
+	ServerSelection ServerSelection
 	// PortForwarding is the settings about port forwarding.
-	PortForwarding PortForwarding `json:"port_forwarding"`
+	PortForwarding PortForwarding
 }

 // TODO v4 remove pointer for receiver (because of Surfshark).
@@ -35,13 +34,13 @@ func (p *Provider) validate(vpnType string, storage Storage) (err error) {
 			providers.Custom,
 			providers.Ivpn,
 			providers.Mullvad,
-			providers.Nordvpn,
 			providers.Surfshark,
 			providers.Windscribe,
 		}
 	}
-	if err = validate.IsOneOf(*p.Name, validNames...); err != nil {
-		return fmt.Errorf("%w for Wireguard: %w", ErrVPNProviderNameNotValid, err)
+	if !helpers.IsOneOf(*p.Name, validNames...) {
+		return fmt.Errorf("%w for Wireguard: %q can only be one of %s",
+			ErrVPNProviderNameNotValid, *p.Name, helpers.ChoicesOrString(validNames))
 	}

 	err = p.ServerSelection.validate(*p.Name, storage)
@@ -59,26 +58,26 @@ func (p *Provider) validate(vpnType string, storage Storage) (err error) {

 func (p *Provider) copy() (copied Provider) {
 	return Provider{
-		Name:            gosettings.CopyPointer(p.Name),
+		Name:            helpers.CopyPointer(p.Name),
 		ServerSelection: p.ServerSelection.copy(),
 		PortForwarding:  p.PortForwarding.copy(),
 	}
 }

 func (p *Provider) mergeWith(other Provider) {
-	p.Name = gosettings.MergeWithPointer(p.Name, other.Name)
+	p.Name = helpers.MergeWithPointer(p.Name, other.Name)
 	p.ServerSelection.mergeWith(other.ServerSelection)
 	p.PortForwarding.mergeWith(other.PortForwarding)
 }

 func (p *Provider) overrideWith(other Provider) {
-	p.Name = gosettings.OverrideWithPointer(p.Name, other.Name)
+	p.Name = helpers.OverrideWithPointer(p.Name, other.Name)
 	p.ServerSelection.overrideWith(other.ServerSelection)
 	p.PortForwarding.overrideWith(other.PortForwarding)
 }

 func (p *Provider) setDefaults() {
-	p.Name = gosettings.DefaultPointer(p.Name, providers.PrivateInternetAccess)
+	p.Name = helpers.DefaultPointer(p.Name, providers.PrivateInternetAccess)
 	p.ServerSelection.setDefaults(*p.Name)
 	p.PortForwarding.setDefaults()
 }
--- a/internal/configuration/settings/publicip.go
+++ b/internal/configuration/settings/publicip.go
@@ -5,7 +5,7 @@ import (
 	"path/filepath"
 	"time"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -42,25 +42,25 @@ func (p PublicIP) validate() (err error) {

 func (p *PublicIP) copy() (copied PublicIP) {
 	return PublicIP{
-		Period:     gosettings.CopyPointer(p.Period),
-		IPFilepath: gosettings.CopyPointer(p.IPFilepath),
+		Period:     helpers.CopyPointer(p.Period),
+		IPFilepath: helpers.CopyPointer(p.IPFilepath),
 	}
 }

 func (p *PublicIP) mergeWith(other PublicIP) {
-	p.Period = gosettings.MergeWithPointer(p.Period, other.Period)
-	p.IPFilepath = gosettings.MergeWithPointer(p.IPFilepath, other.IPFilepath)
+	p.Period = helpers.MergeWithPointer(p.Period, other.Period)
+	p.IPFilepath = helpers.MergeWithPointer(p.IPFilepath, other.IPFilepath)
 }

 func (p *PublicIP) overrideWith(other PublicIP) {
-	p.Period = gosettings.OverrideWithPointer(p.Period, other.Period)
-	p.IPFilepath = gosettings.OverrideWithPointer(p.IPFilepath, other.IPFilepath)
+	p.Period = helpers.OverrideWithPointer(p.Period, other.Period)
+	p.IPFilepath = helpers.OverrideWithPointer(p.IPFilepath, other.IPFilepath)
 }

 func (p *PublicIP) setDefaults() {
 	const defaultPeriod = 12 * time.Hour
-	p.Period = gosettings.DefaultPointer(p.Period, defaultPeriod)
-	p.IPFilepath = gosettings.DefaultPointer(p.IPFilepath, "/tmp/gluetun/ip")
+	p.Period = helpers.DefaultPointer(p.Period, defaultPeriod)
+	p.IPFilepath = helpers.DefaultPointer(p.IPFilepath, "/tmp/gluetun/ip")
 }

 func (p PublicIP) String() string {
--- a/internal/configuration/settings/server.go
+++ b/internal/configuration/settings/server.go
@@ -6,7 +6,7 @@ import (
 	"os"
 	"strconv"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -43,29 +43,29 @@ func (c ControlServer) validate() (err error) {

 func (c *ControlServer) copy() (copied ControlServer) {
 	return ControlServer{
-		Address: gosettings.CopyPointer(c.Address),
-		Log:     gosettings.CopyPointer(c.Log),
+		Address: helpers.CopyPointer(c.Address),
+		Log:     helpers.CopyPointer(c.Log),
 	}
 }

 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (c *ControlServer) mergeWith(other ControlServer) {
-	c.Address = gosettings.MergeWithPointer(c.Address, other.Address)
-	c.Log = gosettings.MergeWithPointer(c.Log, other.Log)
+	c.Address = helpers.MergeWithPointer(c.Address, other.Address)
+	c.Log = helpers.MergeWithPointer(c.Log, other.Log)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (c *ControlServer) overrideWith(other ControlServer) {
-	c.Address = gosettings.OverrideWithPointer(c.Address, other.Address)
-	c.Log = gosettings.OverrideWithPointer(c.Log, other.Log)
+	c.Address = helpers.OverrideWithPointer(c.Address, other.Address)
+	c.Log = helpers.OverrideWithPointer(c.Log, other.Log)
 }

 func (c *ControlServer) setDefaults() {
-	c.Address = gosettings.DefaultPointer(c.Address, ":8000")
-	c.Log = gosettings.DefaultPointer(c.Log, true)
+	c.Address = helpers.DefaultPointer(c.Address, ":8000")
+	c.Log = helpers.DefaultPointer(c.Log, true)
 }

 func (c ControlServer) String() string {
@@ -75,6 +75,6 @@ func (c ControlServer) String() string {
 func (c ControlServer) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Control server settings:")
 	node.Appendf("Listening address: %s", *c.Address)
-	node.Appendf("Logging: %s", gosettings.BoolToYesNo(c.Log))
+	node.Appendf("Logging: %s", helpers.BoolPtrToYesNo(c.Log))
 	return node
 }
--- a/internal/configuration/settings/serverselection.go
+++ b/internal/configuration/settings/serverselection.go
@@ -11,8 +11,6 @@ import (
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 )

@@ -20,50 +18,50 @@ type ServerSelection struct { //nolint:maligned
 	// VPN is the VPN type which can be 'openvpn'
 	// or 'wireguard'. It cannot be the empty string
 	// in the internal state.
-	VPN string `json:"vpn"`
+	VPN string
 	// TargetIP is the server endpoint IP address to use.
 	// It will override any IP address from the picked
 	// built-in server. It cannot be the empty value in the internal
 	// state, and can be set to the unspecified address to indicate
 	// there is not target IP address to use.
-	TargetIP netip.Addr `json:"target_ip"`
+	TargetIP netip.Addr
 	// Counties is the list of countries to filter VPN servers with.
-	Countries []string `json:"countries"`
+	Countries []string
 	// Regions is the list of regions to filter VPN servers with.
-	Regions []string `json:"regions"`
+	Regions []string
 	// Cities is the list of cities to filter VPN servers with.
-	Cities []string `json:"cities"`
+	Cities []string
 	// ISPs is the list of ISP names to filter VPN servers with.
-	ISPs []string `json:"isps"`
+	ISPs []string
 	// Names is the list of server names to filter VPN servers with.
-	Names []string `json:"names"`
+	Names []string
 	// Numbers is the list of server numbers to filter VPN servers with.
-	Numbers []uint16 `json:"numbers"`
+	Numbers []uint16
 	// Hostnames is the list of hostnames to filter VPN servers with.
-	Hostnames []string `json:"hostnames"`
+	Hostnames []string
 	// OwnedOnly is true if VPN provider servers that are not owned
 	// should be filtered. This is used with Mullvad.
-	OwnedOnly *bool `json:"owned_only"`
+	OwnedOnly *bool
 	// FreeOnly is true if VPN servers that are not free should
 	// be filtered. This is used with ProtonVPN and VPN Unlimited.
-	FreeOnly *bool `json:"free_only"`
+	FreeOnly *bool
 	// PremiumOnly is true if VPN servers that are not premium should
 	// be filtered. This is used with VPN Secure.
 	// TODO extend to providers using FreeOnly.
-	PremiumOnly *bool `json:"premium_only"`
+	PremiumOnly *bool
 	// StreamOnly is true if VPN servers not for streaming should
 	// be filtered. This is used with VPNUnlimited.
-	StreamOnly *bool `json:"stream_only"`
+	StreamOnly *bool
 	// MultiHopOnly is true if VPN servers that are not multihop
 	// should be filtered. This is used with Surfshark.
-	MultiHopOnly *bool `json:"multi_hop_only"`
+	MultiHopOnly *bool

 	// OpenVPN contains settings to select OpenVPN servers
 	// and the final connection.
-	OpenVPN OpenVPNSelection `json:"openvpn"`
+	OpenVPN OpenVPNSelection
 	// Wireguard contains settings to select Wireguard servers
 	// and the final connection.
-	Wireguard WireguardSelection `json:"wireguard"`
+	Wireguard WireguardSelection
 }

 var (
@@ -88,17 +86,12 @@ func (ss *ServerSelection) validate(vpnServiceProvider string,
 		return err // already wrapped error
 	}

-	// Retro-compatibility
-	switch vpnServiceProvider {
-	case providers.Nordvpn:
-		*ss = nordvpnRetroRegion(*ss, filterChoices.Regions, filterChoices.Countries)
-	case providers.Surfshark:
-		*ss = surfsharkRetroRegion(*ss)
-	}
-
 	err = validateServerFilters(*ss, filterChoices)
 	if err != nil {
-		return fmt.Errorf("for VPN service provider %s: %w", vpnServiceProvider, err)
+		if errors.Is(err, helpers.ErrNoChoice) {
+			return fmt.Errorf("for VPN service provider %s: %w", vpnServiceProvider, err)
+		}
+		return err // already wrapped error
 	}

 	if *ss.OwnedOnly &&
@@ -167,10 +160,10 @@ func getLocationFilterChoices(vpnServiceProvider string,
 		// // Retro compatibility
 		// TODO v4 remove
 		filterChoices.Regions = append(filterChoices.Regions, validation.SurfsharkRetroLocChoices()...)
-		err := validate.AreAllOneOfCaseInsensitive(ss.Regions, filterChoices.Regions)
-		if err != nil {
-			return models.FilterChoices{}, fmt.Errorf("%w: %w", ErrRegionNotValid, err)
+		if err := helpers.AreAllOneOf(ss.Regions, filterChoices.Regions); err != nil {
+			return models.FilterChoices{}, fmt.Errorf("%w: %s", ErrRegionNotValid, err)
 		}
+		*ss = surfsharkRetroRegion(*ss)
 	}

 	return filterChoices, nil
@@ -179,34 +172,28 @@ func getLocationFilterChoices(vpnServiceProvider string,
 // validateServerFilters validates filters against the choices given as arguments.
 // Set an argument to nil to pass the check for a particular filter.
 func validateServerFilters(settings ServerSelection, filterChoices models.FilterChoices) (err error) {
-	err = validate.AreAllOneOfCaseInsensitive(settings.Countries, filterChoices.Countries)
-	if err != nil {
-		return fmt.Errorf("%w: %w", ErrCountryNotValid, err)
+	if err := helpers.AreAllOneOf(settings.Countries, filterChoices.Countries); err != nil {
+		return fmt.Errorf("%w: %s", ErrCountryNotValid, err)
 	}

-	err = validate.AreAllOneOfCaseInsensitive(settings.Regions, filterChoices.Regions)
-	if err != nil {
-		return fmt.Errorf("%w: %w", ErrRegionNotValid, err)
+	if err := helpers.AreAllOneOf(settings.Regions, filterChoices.Regions); err != nil {
+		return fmt.Errorf("%w: %s", ErrRegionNotValid, err)
 	}

-	err = validate.AreAllOneOfCaseInsensitive(settings.Cities, filterChoices.Cities)
-	if err != nil {
-		return fmt.Errorf("%w: %w", ErrCityNotValid, err)
+	if err := helpers.AreAllOneOf(settings.Cities, filterChoices.Cities); err != nil {
+		return fmt.Errorf("%w: %s", ErrCityNotValid, err)
 	}

-	err = validate.AreAllOneOfCaseInsensitive(settings.ISPs, filterChoices.ISPs)
-	if err != nil {
-		return fmt.Errorf("%w: %w", ErrISPNotValid, err)
+	if err := helpers.AreAllOneOf(settings.ISPs, filterChoices.ISPs); err != nil {
+		return fmt.Errorf("%w: %s", ErrISPNotValid, err)
 	}

-	err = validate.AreAllOneOfCaseInsensitive(settings.Hostnames, filterChoices.Hostnames)
-	if err != nil {
-		return fmt.Errorf("%w: %w", ErrHostnameNotValid, err)
+	if err := helpers.AreAllOneOf(settings.Hostnames, filterChoices.Hostnames); err != nil {
+		return fmt.Errorf("%w: %s", ErrHostnameNotValid, err)
 	}

-	err = validate.AreAllOneOfCaseInsensitive(settings.Names, filterChoices.Names)
-	if err != nil {
-		return fmt.Errorf("%w: %w", ErrNameNotValid, err)
+	if err := helpers.AreAllOneOf(settings.Names, filterChoices.Names); err != nil {
+		return fmt.Errorf("%w: %s", ErrNameNotValid, err)
 	}

 	return nil
@@ -216,70 +203,70 @@ func (ss *ServerSelection) copy() (copied ServerSelection) {
 	return ServerSelection{
 		VPN:          ss.VPN,
 		TargetIP:     ss.TargetIP,
-		Countries:    gosettings.CopySlice(ss.Countries),
-		Regions:      gosettings.CopySlice(ss.Regions),
-		Cities:       gosettings.CopySlice(ss.Cities),
-		ISPs:         gosettings.CopySlice(ss.ISPs),
-		Hostnames:    gosettings.CopySlice(ss.Hostnames),
-		Names:        gosettings.CopySlice(ss.Names),
-		Numbers:      gosettings.CopySlice(ss.Numbers),
-		OwnedOnly:    gosettings.CopyPointer(ss.OwnedOnly),
-		FreeOnly:     gosettings.CopyPointer(ss.FreeOnly),
-		PremiumOnly:  gosettings.CopyPointer(ss.PremiumOnly),
-		StreamOnly:   gosettings.CopyPointer(ss.StreamOnly),
-		MultiHopOnly: gosettings.CopyPointer(ss.MultiHopOnly),
+		Countries:    helpers.CopySlice(ss.Countries),
+		Regions:      helpers.CopySlice(ss.Regions),
+		Cities:       helpers.CopySlice(ss.Cities),
+		ISPs:         helpers.CopySlice(ss.ISPs),
+		Hostnames:    helpers.CopySlice(ss.Hostnames),
+		Names:        helpers.CopySlice(ss.Names),
+		Numbers:      helpers.CopySlice(ss.Numbers),
+		OwnedOnly:    helpers.CopyPointer(ss.OwnedOnly),
+		FreeOnly:     helpers.CopyPointer(ss.FreeOnly),
+		PremiumOnly:  helpers.CopyPointer(ss.PremiumOnly),
+		StreamOnly:   helpers.CopyPointer(ss.StreamOnly),
+		MultiHopOnly: helpers.CopyPointer(ss.MultiHopOnly),
 		OpenVPN:      ss.OpenVPN.copy(),
 		Wireguard:    ss.Wireguard.copy(),
 	}
 }

 func (ss *ServerSelection) mergeWith(other ServerSelection) {
-	ss.VPN = gosettings.MergeWithString(ss.VPN, other.VPN)
-	ss.TargetIP = gosettings.MergeWithValidator(ss.TargetIP, other.TargetIP)
-	ss.Countries = gosettings.MergeWithSlice(ss.Countries, other.Countries)
-	ss.Regions = gosettings.MergeWithSlice(ss.Regions, other.Regions)
-	ss.Cities = gosettings.MergeWithSlice(ss.Cities, other.Cities)
-	ss.ISPs = gosettings.MergeWithSlice(ss.ISPs, other.ISPs)
-	ss.Hostnames = gosettings.MergeWithSlice(ss.Hostnames, other.Hostnames)
-	ss.Names = gosettings.MergeWithSlice(ss.Names, other.Names)
-	ss.Numbers = gosettings.MergeWithSlice(ss.Numbers, other.Numbers)
-	ss.OwnedOnly = gosettings.MergeWithPointer(ss.OwnedOnly, other.OwnedOnly)
-	ss.FreeOnly = gosettings.MergeWithPointer(ss.FreeOnly, other.FreeOnly)
-	ss.PremiumOnly = gosettings.MergeWithPointer(ss.PremiumOnly, other.PremiumOnly)
-	ss.StreamOnly = gosettings.MergeWithPointer(ss.StreamOnly, other.StreamOnly)
-	ss.MultiHopOnly = gosettings.MergeWithPointer(ss.MultiHopOnly, other.MultiHopOnly)
+	ss.VPN = helpers.MergeWithString(ss.VPN, other.VPN)
+	ss.TargetIP = helpers.MergeWithIP(ss.TargetIP, other.TargetIP)
+	ss.Countries = helpers.MergeSlices(ss.Countries, other.Countries)
+	ss.Regions = helpers.MergeSlices(ss.Regions, other.Regions)
+	ss.Cities = helpers.MergeSlices(ss.Cities, other.Cities)
+	ss.ISPs = helpers.MergeSlices(ss.ISPs, other.ISPs)
+	ss.Hostnames = helpers.MergeSlices(ss.Hostnames, other.Hostnames)
+	ss.Names = helpers.MergeSlices(ss.Names, other.Names)
+	ss.Numbers = helpers.MergeSlices(ss.Numbers, other.Numbers)
+	ss.OwnedOnly = helpers.MergeWithPointer(ss.OwnedOnly, other.OwnedOnly)
+	ss.FreeOnly = helpers.MergeWithPointer(ss.FreeOnly, other.FreeOnly)
+	ss.PremiumOnly = helpers.MergeWithPointer(ss.PremiumOnly, other.PremiumOnly)
+	ss.StreamOnly = helpers.MergeWithPointer(ss.StreamOnly, other.StreamOnly)
+	ss.MultiHopOnly = helpers.MergeWithPointer(ss.MultiHopOnly, other.MultiHopOnly)

 	ss.OpenVPN.mergeWith(other.OpenVPN)
 	ss.Wireguard.mergeWith(other.Wireguard)
 }

 func (ss *ServerSelection) overrideWith(other ServerSelection) {
-	ss.VPN = gosettings.OverrideWithString(ss.VPN, other.VPN)
-	ss.TargetIP = gosettings.OverrideWithValidator(ss.TargetIP, other.TargetIP)
-	ss.Countries = gosettings.OverrideWithSlice(ss.Countries, other.Countries)
-	ss.Regions = gosettings.OverrideWithSlice(ss.Regions, other.Regions)
-	ss.Cities = gosettings.OverrideWithSlice(ss.Cities, other.Cities)
-	ss.ISPs = gosettings.OverrideWithSlice(ss.ISPs, other.ISPs)
-	ss.Hostnames = gosettings.OverrideWithSlice(ss.Hostnames, other.Hostnames)
-	ss.Names = gosettings.OverrideWithSlice(ss.Names, other.Names)
-	ss.Numbers = gosettings.OverrideWithSlice(ss.Numbers, other.Numbers)
-	ss.OwnedOnly = gosettings.OverrideWithPointer(ss.OwnedOnly, other.OwnedOnly)
-	ss.FreeOnly = gosettings.OverrideWithPointer(ss.FreeOnly, other.FreeOnly)
-	ss.PremiumOnly = gosettings.OverrideWithPointer(ss.PremiumOnly, other.PremiumOnly)
-	ss.StreamOnly = gosettings.OverrideWithPointer(ss.StreamOnly, other.StreamOnly)
-	ss.MultiHopOnly = gosettings.OverrideWithPointer(ss.MultiHopOnly, other.MultiHopOnly)
+	ss.VPN = helpers.OverrideWithString(ss.VPN, other.VPN)
+	ss.TargetIP = helpers.OverrideWithIP(ss.TargetIP, other.TargetIP)
+	ss.Countries = helpers.OverrideWithSlice(ss.Countries, other.Countries)
+	ss.Regions = helpers.OverrideWithSlice(ss.Regions, other.Regions)
+	ss.Cities = helpers.OverrideWithSlice(ss.Cities, other.Cities)
+	ss.ISPs = helpers.OverrideWithSlice(ss.ISPs, other.ISPs)
+	ss.Hostnames = helpers.OverrideWithSlice(ss.Hostnames, other.Hostnames)
+	ss.Names = helpers.OverrideWithSlice(ss.Names, other.Names)
+	ss.Numbers = helpers.OverrideWithSlice(ss.Numbers, other.Numbers)
+	ss.OwnedOnly = helpers.OverrideWithPointer(ss.OwnedOnly, other.OwnedOnly)
+	ss.FreeOnly = helpers.OverrideWithPointer(ss.FreeOnly, other.FreeOnly)
+	ss.PremiumOnly = helpers.OverrideWithPointer(ss.PremiumOnly, other.PremiumOnly)
+	ss.StreamOnly = helpers.OverrideWithPointer(ss.StreamOnly, other.StreamOnly)
+	ss.MultiHopOnly = helpers.OverrideWithPointer(ss.MultiHopOnly, other.MultiHopOnly)
 	ss.OpenVPN.overrideWith(other.OpenVPN)
 	ss.Wireguard.overrideWith(other.Wireguard)
 }

 func (ss *ServerSelection) setDefaults(vpnProvider string) {
-	ss.VPN = gosettings.DefaultString(ss.VPN, vpn.OpenVPN)
-	ss.TargetIP = gosettings.DefaultValidator(ss.TargetIP, netip.IPv4Unspecified())
-	ss.OwnedOnly = gosettings.DefaultPointer(ss.OwnedOnly, false)
-	ss.FreeOnly = gosettings.DefaultPointer(ss.FreeOnly, false)
-	ss.PremiumOnly = gosettings.DefaultPointer(ss.PremiumOnly, false)
-	ss.StreamOnly = gosettings.DefaultPointer(ss.StreamOnly, false)
-	ss.MultiHopOnly = gosettings.DefaultPointer(ss.MultiHopOnly, false)
+	ss.VPN = helpers.DefaultString(ss.VPN, vpn.OpenVPN)
+	ss.TargetIP = helpers.DefaultIP(ss.TargetIP, netip.IPv4Unspecified())
+	ss.OwnedOnly = helpers.DefaultPointer(ss.OwnedOnly, false)
+	ss.FreeOnly = helpers.DefaultPointer(ss.FreeOnly, false)
+	ss.PremiumOnly = helpers.DefaultPointer(ss.PremiumOnly, false)
+	ss.StreamOnly = helpers.DefaultPointer(ss.StreamOnly, false)
+	ss.MultiHopOnly = helpers.DefaultPointer(ss.MultiHopOnly, false)
 	ss.OpenVPN.setDefaults(vpnProvider)
 	ss.Wireguard.setDefaults()
 }
--- a/internal/configuration/settings/settings.go
+++ b/internal/configuration/settings/settings.go
@@ -4,6 +4,7 @@ import (
 	"fmt"

 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
+	"github.com/qdm12/gluetun/internal/constants/openvpn"
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
@@ -169,14 +170,27 @@ func (s Settings) Warnings() (warnings []string) {

 	if helpers.IsOneOf(*s.VPN.Provider.Name, providers.SlickVPN) &&
 		s.VPN.Type == vpn.OpenVPN {
-		warnings = append(warnings, "OpenVPN 2.5 uses OpenSSL 3 "+
-			"which prohibits the usage of weak security in today's standards. "+
-			*s.VPN.Provider.Name+" uses weak security which is out "+
-			"of Gluetun's control so the only workaround is to allow such weaknesses "+
-			`using the OpenVPN option tls-cipher "DEFAULT:@SECLEVEL=0". `+
-			"You might want to reach to your provider so they upgrade their certificates. "+
-			"Once this is done, you will have to let the Gluetun maintainers know "+
-			"by creating an issue, attaching the new certificate and we will update Gluetun.")
+		if s.VPN.OpenVPN.Version == openvpn.Openvpn24 {
+			warnings = append(warnings, "OpenVPN 2.4 uses OpenSSL 1.1.1 "+
+				"which allows the usage of weak security in today's standards. "+
+				"This can be ok if good security is enforced by the VPN provider. "+
+				"However, "+*s.VPN.Provider.Name+" uses weak security so you should use "+
+				"OpenVPN 2.5 to enforce good security practices.")
+		} else {
+			warnings = append(warnings, "OpenVPN 2.5 uses OpenSSL 3 "+
+				"which prohibits the usage of weak security in today's standards. "+
+				*s.VPN.Provider.Name+" uses weak security which is out "+
+				"of Gluetun's control so the only workaround is to allow such weaknesses "+
+				`using the OpenVPN option tls-cipher "DEFAULT:@SECLEVEL=0". `+
+				"You might want to reach to your provider so they upgrade their certificates. "+
+				"Once this is done, you will have to let the Gluetun maintainers know "+
+				"by creating an issue, attaching the new certificate and we will update Gluetun.")
+		}
+	}
+
+	if s.VPN.OpenVPN.Version == openvpn.Openvpn24 {
+		warnings = append(warnings, "OpenVPN 2.4 will be removed in release v3.34.0 (around June 2023). "+
+			"Please create an issue if you have a compelling reason to keep it.")
 	}

 	return warnings
--- a/internal/configuration/settings/shadowsocks.go
+++ b/internal/configuration/settings/shadowsocks.go
@@ -1,7 +1,7 @@
 package settings

 import (
-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 	"github.com/qdm12/ss-server/pkg/tcpudp"
 )
@@ -21,7 +21,7 @@ func (s Shadowsocks) validate() (err error) {

 func (s *Shadowsocks) copy() (copied Shadowsocks) {
 	return Shadowsocks{
-		Enabled:  gosettings.CopyPointer(s.Enabled),
+		Enabled:  helpers.CopyPointer(s.Enabled),
 		Settings: s.Settings.Copy(),
 	}
 }
@@ -29,20 +29,20 @@ func (s *Shadowsocks) copy() (copied Shadowsocks) {
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (s *Shadowsocks) mergeWith(other Shadowsocks) {
-	s.Enabled = gosettings.MergeWithPointer(s.Enabled, other.Enabled)
-	s.Settings = s.Settings.MergeWith(other.Settings)
+	s.Enabled = helpers.MergeWithPointer(s.Enabled, other.Enabled)
+	s.Settings.MergeWith(other.Settings)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (s *Shadowsocks) overrideWith(other Shadowsocks) {
-	s.Enabled = gosettings.OverrideWithPointer(s.Enabled, other.Enabled)
+	s.Enabled = helpers.OverrideWithPointer(s.Enabled, other.Enabled)
 	s.Settings.OverrideWith(other.Settings)
 }

 func (s *Shadowsocks) setDefaults() {
-	s.Enabled = gosettings.DefaultPointer(s.Enabled, false)
+	s.Enabled = helpers.DefaultPointer(s.Enabled, false)
 	s.Settings.SetDefaults()
 }

@@ -53,16 +53,16 @@ func (s Shadowsocks) String() string {
 func (s Shadowsocks) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Shadowsocks server settings:")

-	node.Appendf("Enabled: %s", gosettings.BoolToYesNo(s.Enabled))
+	node.Appendf("Enabled: %s", helpers.BoolPtrToYesNo(s.Enabled))
 	if !*s.Enabled {
 		return node
 	}

 	// TODO have ToLinesNode in qdm12/ss-server
-	node.Appendf("Listening address: %s", *s.Address)
+	node.Appendf("Listening address: %s", s.Address)
 	node.Appendf("Cipher: %s", s.CipherName)
-	node.Appendf("Password: %s", gosettings.ObfuscateKey(*s.Password))
-	node.Appendf("Log addresses: %s", gosettings.BoolToYesNo(s.LogAddresses))
+	node.Appendf("Password: %s", helpers.ObfuscatePassword(*s.Password))
+	node.Appendf("Log addresses: %s", helpers.BoolPtrToYesNo(s.LogAddresses))

 	return node
 }
--- a/internal/configuration/settings/system.go
+++ b/internal/configuration/settings/system.go
@@ -1,7 +1,7 @@
 package settings

 import (
-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -19,28 +19,28 @@ func (s System) validate() (err error) {

 func (s *System) copy() (copied System) {
 	return System{
-		PUID:     gosettings.CopyPointer(s.PUID),
-		PGID:     gosettings.CopyPointer(s.PGID),
+		PUID:     helpers.CopyPointer(s.PUID),
+		PGID:     helpers.CopyPointer(s.PGID),
 		Timezone: s.Timezone,
 	}
 }

 func (s *System) mergeWith(other System) {
-	s.PUID = gosettings.MergeWithPointer(s.PUID, other.PUID)
-	s.PGID = gosettings.MergeWithPointer(s.PGID, other.PGID)
-	s.Timezone = gosettings.MergeWithString(s.Timezone, other.Timezone)
+	s.PUID = helpers.MergeWithPointer(s.PUID, other.PUID)
+	s.PGID = helpers.MergeWithPointer(s.PGID, other.PGID)
+	s.Timezone = helpers.MergeWithString(s.Timezone, other.Timezone)
 }

 func (s *System) overrideWith(other System) {
-	s.PUID = gosettings.OverrideWithPointer(s.PUID, other.PUID)
-	s.PGID = gosettings.OverrideWithPointer(s.PGID, other.PGID)
-	s.Timezone = gosettings.OverrideWithString(s.Timezone, other.Timezone)
+	s.PUID = helpers.OverrideWithPointer(s.PUID, other.PUID)
+	s.PGID = helpers.OverrideWithPointer(s.PGID, other.PGID)
+	s.Timezone = helpers.OverrideWithString(s.Timezone, other.Timezone)
 }

 func (s *System) setDefaults() {
 	const defaultID = 1000
-	s.PUID = gosettings.DefaultPointer(s.PUID, defaultID)
-	s.PGID = gosettings.DefaultPointer(s.PGID, defaultID)
+	s.PUID = helpers.DefaultPointer(s.PUID, defaultID)
+	s.PGID = helpers.DefaultPointer(s.PGID, defaultID)
 }

 func (s System) String() string {
--- a/internal/configuration/settings/unbound.go
+++ b/internal/configuration/settings/unbound.go
@@ -7,20 +7,20 @@ import (

 	"github.com/qdm12/dns/pkg/provider"
 	"github.com/qdm12/dns/pkg/unbound"
-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

 // Unbound is settings for the Unbound program.
 type Unbound struct {
-	Providers             []string       `json:"providers"`
-	Caching               *bool          `json:"caching"`
-	IPv6                  *bool          `json:"ipv6"`
-	VerbosityLevel        *uint8         `json:"verbosity_level"`
-	VerbosityDetailsLevel *uint8         `json:"verbosity_details_level"`
-	ValidationLogLevel    *uint8         `json:"validation_log_level"`
-	Username              string         `json:"username"`
-	Allowed               []netip.Prefix `json:"allowed"`
+	Providers             []string
+	Caching               *bool
+	IPv6                  *bool
+	VerbosityLevel        *uint8
+	VerbosityDetailsLevel *uint8
+	ValidationLogLevel    *uint8
+	Username              string
+	Allowed               []netip.Prefix
 }

 func (u *Unbound) setDefaults() {
@@ -30,17 +30,17 @@ func (u *Unbound) setDefaults() {
 		}
 	}

-	u.Caching = gosettings.DefaultPointer(u.Caching, true)
-	u.IPv6 = gosettings.DefaultPointer(u.IPv6, false)
+	u.Caching = helpers.DefaultPointer(u.Caching, true)
+	u.IPv6 = helpers.DefaultPointer(u.IPv6, false)

 	const defaultVerbosityLevel = 1
-	u.VerbosityLevel = gosettings.DefaultPointer(u.VerbosityLevel, defaultVerbosityLevel)
+	u.VerbosityLevel = helpers.DefaultPointer(u.VerbosityLevel, defaultVerbosityLevel)

 	const defaultVerbosityDetailsLevel = 0
-	u.VerbosityDetailsLevel = gosettings.DefaultPointer(u.VerbosityDetailsLevel, defaultVerbosityDetailsLevel)
+	u.VerbosityDetailsLevel = helpers.DefaultPointer(u.VerbosityDetailsLevel, defaultVerbosityDetailsLevel)

 	const defaultValidationLogLevel = 0
-	u.ValidationLogLevel = gosettings.DefaultPointer(u.ValidationLogLevel, defaultValidationLogLevel)
+	u.ValidationLogLevel = helpers.DefaultPointer(u.ValidationLogLevel, defaultValidationLogLevel)

 	if u.Allowed == nil {
 		u.Allowed = []netip.Prefix{
@@ -49,7 +49,7 @@ func (u *Unbound) setDefaults() {
 		}
 	}

-	u.Username = gosettings.DefaultString(u.Username, "root")
+	u.Username = helpers.DefaultString(u.Username, "root")
 }

 var (
@@ -94,37 +94,37 @@ func (u Unbound) validate() (err error) {

 func (u Unbound) copy() (copied Unbound) {
 	return Unbound{
-		Providers:             gosettings.CopySlice(u.Providers),
-		Caching:               gosettings.CopyPointer(u.Caching),
-		IPv6:                  gosettings.CopyPointer(u.IPv6),
-		VerbosityLevel:        gosettings.CopyPointer(u.VerbosityLevel),
-		VerbosityDetailsLevel: gosettings.CopyPointer(u.VerbosityDetailsLevel),
-		ValidationLogLevel:    gosettings.CopyPointer(u.ValidationLogLevel),
+		Providers:             helpers.CopySlice(u.Providers),
+		Caching:               helpers.CopyPointer(u.Caching),
+		IPv6:                  helpers.CopyPointer(u.IPv6),
+		VerbosityLevel:        helpers.CopyPointer(u.VerbosityLevel),
+		VerbosityDetailsLevel: helpers.CopyPointer(u.VerbosityDetailsLevel),
+		ValidationLogLevel:    helpers.CopyPointer(u.ValidationLogLevel),
 		Username:              u.Username,
-		Allowed:               gosettings.CopySlice(u.Allowed),
+		Allowed:               helpers.CopySlice(u.Allowed),
 	}
 }

 func (u *Unbound) mergeWith(other Unbound) {
-	u.Providers = gosettings.MergeWithSlice(u.Providers, other.Providers)
-	u.Caching = gosettings.MergeWithPointer(u.Caching, other.Caching)
-	u.IPv6 = gosettings.MergeWithPointer(u.IPv6, other.IPv6)
-	u.VerbosityLevel = gosettings.MergeWithPointer(u.VerbosityLevel, other.VerbosityLevel)
-	u.VerbosityDetailsLevel = gosettings.MergeWithPointer(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
-	u.ValidationLogLevel = gosettings.MergeWithPointer(u.ValidationLogLevel, other.ValidationLogLevel)
-	u.Username = gosettings.MergeWithString(u.Username, other.Username)
-	u.Allowed = gosettings.MergeWithSlice(u.Allowed, other.Allowed)
+	u.Providers = helpers.MergeSlices(u.Providers, other.Providers)
+	u.Caching = helpers.MergeWithPointer(u.Caching, other.Caching)
+	u.IPv6 = helpers.MergeWithPointer(u.IPv6, other.IPv6)
+	u.VerbosityLevel = helpers.MergeWithPointer(u.VerbosityLevel, other.VerbosityLevel)
+	u.VerbosityDetailsLevel = helpers.MergeWithPointer(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
+	u.ValidationLogLevel = helpers.MergeWithPointer(u.ValidationLogLevel, other.ValidationLogLevel)
+	u.Username = helpers.MergeWithString(u.Username, other.Username)
+	u.Allowed = helpers.MergeSlices(u.Allowed, other.Allowed)
 }

 func (u *Unbound) overrideWith(other Unbound) {
-	u.Providers = gosettings.OverrideWithSlice(u.Providers, other.Providers)
-	u.Caching = gosettings.OverrideWithPointer(u.Caching, other.Caching)
-	u.IPv6 = gosettings.OverrideWithPointer(u.IPv6, other.IPv6)
-	u.VerbosityLevel = gosettings.OverrideWithPointer(u.VerbosityLevel, other.VerbosityLevel)
-	u.VerbosityDetailsLevel = gosettings.OverrideWithPointer(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
-	u.ValidationLogLevel = gosettings.OverrideWithPointer(u.ValidationLogLevel, other.ValidationLogLevel)
-	u.Username = gosettings.OverrideWithString(u.Username, other.Username)
-	u.Allowed = gosettings.OverrideWithSlice(u.Allowed, other.Allowed)
+	u.Providers = helpers.OverrideWithSlice(u.Providers, other.Providers)
+	u.Caching = helpers.OverrideWithPointer(u.Caching, other.Caching)
+	u.IPv6 = helpers.OverrideWithPointer(u.IPv6, other.IPv6)
+	u.VerbosityLevel = helpers.OverrideWithPointer(u.VerbosityLevel, other.VerbosityLevel)
+	u.VerbosityDetailsLevel = helpers.OverrideWithPointer(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
+	u.ValidationLogLevel = helpers.OverrideWithPointer(u.ValidationLogLevel, other.ValidationLogLevel)
+	u.Username = helpers.OverrideWithString(u.Username, other.Username)
+	u.Allowed = helpers.OverrideWithSlice(u.Allowed, other.Allowed)
 }

 func (u Unbound) ToUnboundFormat() (settings unbound.Settings, err error) {
@@ -186,8 +186,8 @@ func (u Unbound) toLinesNode() (node *gotree.Node) {
 		authServers.Appendf(provider)
 	}

-	node.Appendf("Caching: %s", gosettings.BoolToYesNo(u.Caching))
-	node.Appendf("IPv6: %s", gosettings.BoolToYesNo(u.IPv6))
+	node.Appendf("Caching: %s", helpers.BoolPtrToYesNo(u.Caching))
+	node.Appendf("IPv6: %s", helpers.BoolPtrToYesNo(u.IPv6))
 	node.Appendf("Verbosity level: %d", *u.VerbosityLevel)
 	node.Appendf("Verbosity details level: %d", *u.VerbosityDetailsLevel)
 	node.Appendf("Validation log level: %d", *u.ValidationLogLevel)
--- a/internal/configuration/settings/unbound_test.go
+++ b/internal/configuration/settings/unbound_test.go
@@ -29,9 +29,9 @@ func Test_Unbound_JSON(t *testing.T) {
 	b, err := json.Marshal(settings)
 	require.NoError(t, err)

-	const expected = `{"providers":["cloudflare"],"caching":true,"ipv6":false,` +
-		`"verbosity_level":1,"verbosity_details_level":null,"validation_log_level":0,` +
-		`"username":"user","allowed":["0.0.0.0/0","::/0"]}`
+	const expected = `{"Providers":["cloudflare"],"Caching":true,"IPv6":false,` +
+		`"VerbosityLevel":1,"VerbosityDetailsLevel":null,"ValidationLogLevel":0,` +
+		`"Username":"user","Allowed":["0.0.0.0/0","::/0"]}`

 	assert.Equal(t, expected, string(b))

--- a/internal/configuration/settings/updater.go
+++ b/internal/configuration/settings/updater.go
@@ -5,9 +5,8 @@ import (
 	"strings"
 	"time"

+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 )

@@ -46,9 +45,16 @@ func (u Updater) Validate() (err error) {

 	validProviders := providers.All()
 	for _, provider := range u.Providers {
-		err = validate.IsOneOf(provider, validProviders...)
-		if err != nil {
-			return fmt.Errorf("%w: %w", ErrVPNProviderNameNotValid, err)
+		valid := false
+		for _, validProvider := range validProviders {
+			if provider == validProvider {
+				valid = true
+				break
+			}
+		}
+		if !valid {
+			return fmt.Errorf("%w: %q can only be one of %s",
+				ErrVPNProviderNameNotValid, provider, helpers.ChoicesOrString(validProviders))
 		}
 	}

@@ -57,35 +63,35 @@ func (u Updater) Validate() (err error) {

 func (u *Updater) copy() (copied Updater) {
 	return Updater{
-		Period:     gosettings.CopyPointer(u.Period),
+		Period:     helpers.CopyPointer(u.Period),
 		DNSAddress: u.DNSAddress,
 		MinRatio:   u.MinRatio,
-		Providers:  gosettings.CopySlice(u.Providers),
+		Providers:  helpers.CopySlice(u.Providers),
 	}
 }

 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (u *Updater) mergeWith(other Updater) {
-	u.Period = gosettings.MergeWithPointer(u.Period, other.Period)
-	u.DNSAddress = gosettings.MergeWithString(u.DNSAddress, other.DNSAddress)
-	u.MinRatio = gosettings.MergeWithNumber(u.MinRatio, other.MinRatio)
-	u.Providers = gosettings.MergeWithSlice(u.Providers, other.Providers)
+	u.Period = helpers.MergeWithPointer(u.Period, other.Period)
+	u.DNSAddress = helpers.MergeWithString(u.DNSAddress, other.DNSAddress)
+	u.MinRatio = helpers.MergeWithNumber(u.MinRatio, other.MinRatio)
+	u.Providers = helpers.MergeSlices(u.Providers, other.Providers)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (u *Updater) overrideWith(other Updater) {
-	u.Period = gosettings.OverrideWithPointer(u.Period, other.Period)
-	u.DNSAddress = gosettings.OverrideWithString(u.DNSAddress, other.DNSAddress)
-	u.MinRatio = gosettings.OverrideWithNumber(u.MinRatio, other.MinRatio)
-	u.Providers = gosettings.OverrideWithSlice(u.Providers, other.Providers)
+	u.Period = helpers.OverrideWithPointer(u.Period, other.Period)
+	u.DNSAddress = helpers.OverrideWithString(u.DNSAddress, other.DNSAddress)
+	u.MinRatio = helpers.OverrideWithNumber(u.MinRatio, other.MinRatio)
+	u.Providers = helpers.OverrideWithSlice(u.Providers, other.Providers)
 }

 func (u *Updater) SetDefaults(vpnProvider string) {
-	u.Period = gosettings.DefaultPointer(u.Period, 0)
-	u.DNSAddress = gosettings.DefaultString(u.DNSAddress, "1.1.1.1:53")
+	u.Period = helpers.DefaultPointer(u.Period, 0)
+	u.DNSAddress = helpers.DefaultString(u.DNSAddress, "1.1.1.1:53")

 	if u.MinRatio == 0 {
 		const defaultMinRatio = 0.8
--- a/internal/configuration/settings/version.go
+++ b/internal/configuration/settings/version.go
@@ -1,7 +1,7 @@
 package settings

 import (
-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 )

@@ -19,25 +19,25 @@ func (v Version) validate() (err error) {

 func (v *Version) copy() (copied Version) {
 	return Version{
-		Enabled: gosettings.CopyPointer(v.Enabled),
+		Enabled: helpers.CopyPointer(v.Enabled),
 	}
 }

 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (v *Version) mergeWith(other Version) {
-	v.Enabled = gosettings.MergeWithPointer(v.Enabled, other.Enabled)
+	v.Enabled = helpers.MergeWithPointer(v.Enabled, other.Enabled)
 }

 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (v *Version) overrideWith(other Version) {
-	v.Enabled = gosettings.OverrideWithPointer(v.Enabled, other.Enabled)
+	v.Enabled = helpers.OverrideWithPointer(v.Enabled, other.Enabled)
 }

 func (v *Version) setDefaults() {
-	v.Enabled = gosettings.DefaultPointer(v.Enabled, true)
+	v.Enabled = helpers.DefaultPointer(v.Enabled, true)
 }

 func (v Version) String() string {
@@ -47,7 +47,7 @@ func (v Version) String() string {
 func (v Version) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Version settings:")

-	node.Appendf("Enabled: %s", gosettings.BoolToYesNo(v.Enabled))
+	node.Appendf("Enabled: %s", helpers.BoolPtrToYesNo(v.Enabled))

 	return node
 }
--- a/internal/configuration/settings/vpn.go
+++ b/internal/configuration/settings/vpn.go
@@ -2,10 +2,10 @@ package settings

 import (
 	"fmt"
+	"strings"

+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/vpn"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 )

@@ -13,18 +13,19 @@ type VPN struct {
 	// Type is the VPN type and can only be
 	// 'openvpn' or 'wireguard'. It cannot be the
 	// empty string in the internal state.
-	Type      string    `json:"type"`
-	Provider  Provider  `json:"provider"`
-	OpenVPN   OpenVPN   `json:"openvpn"`
-	Wireguard Wireguard `json:"wireguard"`
+	Type      string
+	Provider  Provider
+	OpenVPN   OpenVPN
+	Wireguard Wireguard
 }

 // TODO v4 remove pointer for receiver (because of Surfshark).
 func (v *VPN) Validate(storage Storage, ipv6Supported bool) (err error) {
 	// Validate Type
 	validVPNTypes := []string{vpn.OpenVPN, vpn.Wireguard}
-	if err = validate.IsOneOf(v.Type, validVPNTypes...); err != nil {
-		return fmt.Errorf("%w: %w", ErrVPNTypeNotValid, err)
+	if !helpers.IsOneOf(v.Type, validVPNTypes...) {
+		return fmt.Errorf("%w: %q and can only be one of %s",
+			ErrVPNTypeNotValid, v.Type, strings.Join(validVPNTypes, ", "))
 	}

 	err = v.Provider.validate(v.Type, storage)
@@ -57,24 +58,24 @@ func (v *VPN) Copy() (copied VPN) {
 }

 func (v *VPN) mergeWith(other VPN) {
-	v.Type = gosettings.MergeWithString(v.Type, other.Type)
+	v.Type = helpers.MergeWithString(v.Type, other.Type)
 	v.Provider.mergeWith(other.Provider)
 	v.OpenVPN.mergeWith(other.OpenVPN)
 	v.Wireguard.mergeWith(other.Wireguard)
 }

 func (v *VPN) OverrideWith(other VPN) {
-	v.Type = gosettings.OverrideWithString(v.Type, other.Type)
+	v.Type = helpers.OverrideWithString(v.Type, other.Type)
 	v.Provider.overrideWith(other.Provider)
 	v.OpenVPN.overrideWith(other.OpenVPN)
 	v.Wireguard.overrideWith(other.Wireguard)
 }

 func (v *VPN) setDefaults() {
-	v.Type = gosettings.DefaultString(v.Type, vpn.OpenVPN)
+	v.Type = helpers.DefaultString(v.Type, vpn.OpenVPN)
 	v.Provider.setDefaults()
 	v.OpenVPN.setDefaults(*v.Provider.Name)
-	v.Wireguard.setDefaults(*v.Provider.Name)
+	v.Wireguard.setDefaults()
 }

 func (v VPN) String() string {
--- a/internal/configuration/settings/wireguard.go
+++ b/internal/configuration/settings/wireguard.go
@@ -7,8 +7,6 @@ import (

 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 )
@@ -17,29 +15,23 @@ import (
 type Wireguard struct {
 	// PrivateKey is the Wireguard client peer private key.
 	// It cannot be nil in the internal state.
-	PrivateKey *string `json:"private_key"`
+	PrivateKey *string
 	// PreSharedKey is the Wireguard pre-shared key.
 	// It can be the empty string to indicate there
 	// is no pre-shared key.
 	// It cannot be nil in the internal state.
-	PreSharedKey *string `json:"pre_shared_key"`
+	PreSharedKey *string
 	// Addresses are the Wireguard interface addresses.
-	Addresses []netip.Prefix `json:"addresses"`
+	Addresses []netip.Prefix
 	// Interface is the name of the Wireguard interface
 	// to create. It cannot be the empty string in the
 	// internal state.
-	Interface string `json:"interface"`
-	// Maximum Transmission Unit (MTU) of the Wireguard interface.
-	// It cannot be zero in the internal state, and defaults to
-	// 1400. Note it is not the wireguard-go MTU default of 1420
-	// because this impacts bandwidth a lot on some VPN providers,
-	// see https://github.com/qdm12/gluetun/issues/1650.
-	MTU uint16 `json:"mtu"`
+	Interface string
 	// Implementation is the Wireguard implementation to use.
 	// It can be "auto", "userspace" or "kernelspace".
 	// It defaults to "auto" and cannot be the empty string
 	// in the internal state.
-	Implementation string `json:"implementation"`
+	Implementation string
 }

 var regexpInterfaceName = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)
@@ -48,11 +40,9 @@ var regexpInterfaceName = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)
 // It should only be ran if the VPN type chosen is Wireguard.
 func (w Wireguard) validate(vpnProvider string, ipv6Supported bool) (err error) {
 	if !helpers.IsOneOf(vpnProvider,
-		providers.Airvpn,
 		providers.Custom,
 		providers.Ivpn,
 		providers.Mullvad,
-		providers.Nordvpn,
 		providers.Surfshark,
 		providers.Windscribe,
 	) {
@@ -106,8 +96,9 @@ func (w Wireguard) validate(vpnProvider string, ipv6Supported bool) (err error)
 	}

 	validImplementations := []string{"auto", "userspace", "kernelspace"}
-	if err := validate.IsOneOf(w.Implementation, validImplementations...); err != nil {
-		return fmt.Errorf("%w: %w", ErrWireguardImplementationNotValid, err)
+	if !helpers.IsOneOf(w.Implementation, validImplementations...) {
+		return fmt.Errorf("%w: %s must be one of %s", ErrWireguardImplementationNotValid,
+			w.Implementation, helpers.ChoicesOrString(validImplementations))
 	}

 	return nil
@@ -115,45 +106,35 @@ func (w Wireguard) validate(vpnProvider string, ipv6Supported bool) (err error)

 func (w *Wireguard) copy() (copied Wireguard) {
 	return Wireguard{
-		PrivateKey:     gosettings.CopyPointer(w.PrivateKey),
-		PreSharedKey:   gosettings.CopyPointer(w.PreSharedKey),
-		Addresses:      gosettings.CopySlice(w.Addresses),
+		PrivateKey:     helpers.CopyPointer(w.PrivateKey),
+		PreSharedKey:   helpers.CopyPointer(w.PreSharedKey),
+		Addresses:      helpers.CopySlice(w.Addresses),
 		Interface:      w.Interface,
-		MTU:            w.MTU,
 		Implementation: w.Implementation,
 	}
 }

 func (w *Wireguard) mergeWith(other Wireguard) {
-	w.PrivateKey = gosettings.MergeWithPointer(w.PrivateKey, other.PrivateKey)
-	w.PreSharedKey = gosettings.MergeWithPointer(w.PreSharedKey, other.PreSharedKey)
-	w.Addresses = gosettings.MergeWithSlice(w.Addresses, other.Addresses)
-	w.Interface = gosettings.MergeWithString(w.Interface, other.Interface)
-	w.MTU = gosettings.MergeWithNumber(w.MTU, other.MTU)
-	w.Implementation = gosettings.MergeWithString(w.Implementation, other.Implementation)
+	w.PrivateKey = helpers.MergeWithPointer(w.PrivateKey, other.PrivateKey)
+	w.PreSharedKey = helpers.MergeWithPointer(w.PreSharedKey, other.PreSharedKey)
+	w.Addresses = helpers.MergeSlices(w.Addresses, other.Addresses)
+	w.Interface = helpers.MergeWithString(w.Interface, other.Interface)
+	w.Implementation = helpers.MergeWithString(w.Implementation, other.Implementation)
 }

 func (w *Wireguard) overrideWith(other Wireguard) {
-	w.PrivateKey = gosettings.OverrideWithPointer(w.PrivateKey, other.PrivateKey)
-	w.PreSharedKey = gosettings.OverrideWithPointer(w.PreSharedKey, other.PreSharedKey)
-	w.Addresses = gosettings.OverrideWithSlice(w.Addresses, other.Addresses)
-	w.Interface = gosettings.OverrideWithString(w.Interface, other.Interface)
-	w.MTU = gosettings.OverrideWithNumber(w.MTU, other.MTU)
-	w.Implementation = gosettings.OverrideWithString(w.Implementation, other.Implementation)
+	w.PrivateKey = helpers.OverrideWithPointer(w.PrivateKey, other.PrivateKey)
+	w.PreSharedKey = helpers.OverrideWithPointer(w.PreSharedKey, other.PreSharedKey)
+	w.Addresses = helpers.OverrideWithSlice(w.Addresses, other.Addresses)
+	w.Interface = helpers.OverrideWithString(w.Interface, other.Interface)
+	w.Implementation = helpers.OverrideWithString(w.Implementation, other.Implementation)
 }

-func (w *Wireguard) setDefaults(vpnProvider string) {
-	w.PrivateKey = gosettings.DefaultPointer(w.PrivateKey, "")
-	w.PreSharedKey = gosettings.DefaultPointer(w.PreSharedKey, "")
-	if vpnProvider == providers.Nordvpn {
-		defaultNordVPNAddress := netip.AddrFrom4([4]byte{10, 5, 0, 2})
-		defaultNordVPNPrefix := netip.PrefixFrom(defaultNordVPNAddress, defaultNordVPNAddress.BitLen())
-		w.Addresses = gosettings.DefaultSlice(w.Addresses, []netip.Prefix{defaultNordVPNPrefix})
-	}
-	w.Interface = gosettings.DefaultString(w.Interface, "wg0")
-	const defaultMTU = 1400
-	w.MTU = gosettings.DefaultNumber(w.MTU, defaultMTU)
-	w.Implementation = gosettings.DefaultString(w.Implementation, "auto")
+func (w *Wireguard) setDefaults() {
+	w.PrivateKey = helpers.DefaultPointer(w.PrivateKey, "")
+	w.PreSharedKey = helpers.DefaultPointer(w.PreSharedKey, "")
+	w.Interface = helpers.DefaultString(w.Interface, "wg0")
+	w.Implementation = helpers.DefaultString(w.Implementation, "auto")
 }

 func (w Wireguard) String() string {
@@ -164,12 +145,12 @@ func (w Wireguard) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Wireguard settings:")

 	if *w.PrivateKey != "" {
-		s := gosettings.ObfuscateKey(*w.PrivateKey)
+		s := helpers.ObfuscateWireguardKey(*w.PrivateKey)
 		node.Appendf("Private key: %s", s)
 	}

 	if *w.PreSharedKey != "" {
-		s := gosettings.ObfuscateKey(*w.PreSharedKey)
+		s := helpers.ObfuscateWireguardKey(*w.PreSharedKey)
 		node.Appendf("Pre-shared key: %s", s)
 	}

@@ -178,8 +159,7 @@ func (w Wireguard) toLinesNode() (node *gotree.Node) {
 		addressesNode.Appendf(address.String())
 	}

-	interfaceNode := node.Appendf("Network interface: %s", w.Interface)
-	interfaceNode.Appendf("MTU: %d", w.MTU)
+	node.Appendf("Network interface: %s", w.Interface)

 	if w.Implementation != "auto" {
 		node.Appendf("Implementation: %s", w.Implementation)
--- a/internal/configuration/settings/wireguardselection.go
+++ b/internal/configuration/settings/wireguardselection.go
@@ -4,9 +4,8 @@ import (
 	"fmt"
 	"net/netip"

+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
-	"github.com/qdm12/gosettings"
-	"github.com/qdm12/gosettings/validate"
 	"github.com/qdm12/gotree"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 )
@@ -18,18 +17,18 @@ type WireguardSelection struct {
 	// To indicate it should not be used, it should be set
 	// to netaddr.IPv4Unspecified(). It can never be the zero value
 	// in the internal state.
-	EndpointIP netip.Addr `json:"endpoint_ip"`
+	EndpointIP netip.Addr
 	// EndpointPort is a the server port to use for the VPN server.
 	// It is optional for VPN providers IVPN, Mullvad, Surfshark
 	// and Windscribe, and compulsory for the others.
 	// When optional, it can be set to 0 to indicate not use
 	// a custom endpoint port. It cannot be nil in the internal
 	// state.
-	EndpointPort *uint16 `json:"endpoint_port"`
+	EndpointPort *uint16
 	// PublicKey is the server public key.
 	// It is only used with VPN providers generating Wireguard
 	// configurations specific to each server and user.
-	PublicKey string `json:"public_key"`
+	PublicKey string
 }

 // Validate validates WireguardSelection settings.
@@ -38,7 +37,7 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 	// Validate EndpointIP
 	switch vpnProvider {
 	case providers.Airvpn, providers.Ivpn, providers.Mullvad,
-		providers.Nordvpn, providers.Surfshark, providers.Windscribe:
+		providers.Surfshark, providers.Windscribe:
 		// endpoint IP addresses are baked in
 	case providers.Custom:
 		if !w.EndpointIP.IsValid() || w.EndpointIP.IsUnspecified() {
@@ -55,7 +54,7 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 			return fmt.Errorf("%w", ErrWireguardEndpointPortNotSet)
 		}
 	// EndpointPort cannot be set
-	case providers.Surfshark, providers.Nordvpn:
+	case providers.Surfshark:
 		if *w.EndpointPort != 0 {
 			return fmt.Errorf("%w", ErrWireguardEndpointPortSet)
 		}
@@ -77,12 +76,12 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 			allowed = []uint16{53, 80, 123, 443, 1194, 65142}
 		}

-		err = validate.IsOneOf(*w.EndpointPort, allowed...)
-		if err == nil {
+		if helpers.Uint16IsOneOf(*w.EndpointPort, allowed) {
 			break
 		}
-		return fmt.Errorf("%w: for VPN service provider %s: %w",
-			ErrWireguardEndpointPortNotAllowed, vpnProvider, err)
+		return fmt.Errorf("%w: %d for VPN service provider %s; %s",
+			ErrWireguardEndpointPortNotAllowed, w.EndpointPort, vpnProvider,
+			helpers.PortChoicesOrString(allowed))
 	default: // Providers not supporting Wireguard
 	}

@@ -111,26 +110,26 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 func (w *WireguardSelection) copy() (copied WireguardSelection) {
 	return WireguardSelection{
 		EndpointIP:   w.EndpointIP,
-		EndpointPort: gosettings.CopyPointer(w.EndpointPort),
+		EndpointPort: helpers.CopyPointer(w.EndpointPort),
 		PublicKey:    w.PublicKey,
 	}
 }

 func (w *WireguardSelection) mergeWith(other WireguardSelection) {
-	w.EndpointIP = gosettings.MergeWithValidator(w.EndpointIP, other.EndpointIP)
-	w.EndpointPort = gosettings.MergeWithPointer(w.EndpointPort, other.EndpointPort)
-	w.PublicKey = gosettings.MergeWithString(w.PublicKey, other.PublicKey)
+	w.EndpointIP = helpers.MergeWithIP(w.EndpointIP, other.EndpointIP)
+	w.EndpointPort = helpers.MergeWithPointer(w.EndpointPort, other.EndpointPort)
+	w.PublicKey = helpers.MergeWithString(w.PublicKey, other.PublicKey)
 }

 func (w *WireguardSelection) overrideWith(other WireguardSelection) {
-	w.EndpointIP = gosettings.OverrideWithValidator(w.EndpointIP, other.EndpointIP)
-	w.EndpointPort = gosettings.OverrideWithPointer(w.EndpointPort, other.EndpointPort)
-	w.PublicKey = gosettings.OverrideWithString(w.PublicKey, other.PublicKey)
+	w.EndpointIP = helpers.OverrideWithIP(w.EndpointIP, other.EndpointIP)
+	w.EndpointPort = helpers.OverrideWithPointer(w.EndpointPort, other.EndpointPort)
+	w.PublicKey = helpers.OverrideWithString(w.PublicKey, other.PublicKey)
 }

 func (w *WireguardSelection) setDefaults() {
-	w.EndpointIP = gosettings.DefaultValidator(w.EndpointIP, netip.IPv4Unspecified())
-	w.EndpointPort = gosettings.DefaultPointer(w.EndpointPort, 0)
+	w.EndpointIP = helpers.DefaultIP(w.EndpointIP, netip.IPv4Unspecified())
+	w.EndpointPort = helpers.DefaultPointer(w.EndpointPort, 0)
 }

 func (w WireguardSelection) String() string {
--- a/internal/configuration/sources/env/dns.go
+++ b/internal/configuration/sources/env/dns.go
@@ -13,9 +13,9 @@ func (s *Source) readDNS() (dns settings.DNS, err error) {
 		return dns, err
 	}

-	dns.KeepNameserver, err = s.env.BoolPtr("DNS_KEEP_NAMESERVER")
+	dns.KeepNameserver, err = envToBoolPtr("DNS_KEEP_NAMESERVER")
 	if err != nil {
-		return dns, err
+		return dns, fmt.Errorf("environment variable DNS_KEEP_NAMESERVER: %w", err)
 	}

 	dns.DoT, err = s.readDoT()
@@ -27,24 +27,19 @@ func (s *Source) readDNS() (dns settings.DNS, err error) {
 }

 func (s *Source) readDNSServerAddress() (address netip.Addr, err error) {
-	const currentKey = "DNS_ADDRESS"
-	key := firstKeySet(s.env, "DNS_PLAINTEXT_ADDRESS", currentKey)
-	switch key {
-	case "":
+	key, value := s.getEnvWithRetro("DNS_ADDRESS", "DNS_PLAINTEXT_ADDRESS")
+	if value == "" {
 		return address, nil
-	case currentKey:
-	default: // Retro-compatibility
-		s.handleDeprecatedKey(key, currentKey)
 	}

-	address, err = s.env.NetipAddr(key)
+	address, err = netip.ParseAddr(value)
 	if err != nil {
-		return address, err
+		return address, fmt.Errorf("environment variable %s: %w", key, err)
 	}

 	// TODO remove in v4
 	if address.Unmap().Compare(netip.AddrFrom4([4]byte{127, 0, 0, 1})) != 0 {
-		s.warner.Warn(key + " is set to " + address.String() +
+		s.warner.Warn(key + " is set to " + value +
 			" so the DNS over TLS (DoT) server will not be used." +
 			" The default value changed to 127.0.0.1 so it uses the internal DoT serves." +
 			" If the DoT server fails to start, the IPv4 address of the first plaintext DNS server" +
--- a/internal/configuration/sources/env/dnsblacklist.go
+++ b/internal/configuration/sources/env/dnsblacklist.go
@@ -6,44 +6,58 @@ import (
 	"net/netip"

 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
+	"github.com/qdm12/govalid/binary"
 )

 func (s *Source) readDNSBlacklist() (blacklist settings.DNSBlacklist, err error) {
-	blacklist.BlockMalicious, err = s.env.BoolPtr("BLOCK_MALICIOUS")
+	blacklist.BlockMalicious, err = envToBoolPtr("BLOCK_MALICIOUS")
+	if err != nil {
+		return blacklist, fmt.Errorf("environment variable BLOCK_MALICIOUS: %w", err)
+	}
+
+	blacklist.BlockSurveillance, err = s.readBlockSurveillance()
 	if err != nil {
 		return blacklist, err
 	}

-	blacklist.BlockSurveillance, err = s.env.BoolPtr("BLOCK_SURVEILLANCE",
-		env.RetroKeys("BLOCK_NSA"))
+	blacklist.BlockAds, err = envToBoolPtr("BLOCK_ADS")
 	if err != nil {
-		return blacklist, err
-	}
-
-	blacklist.BlockAds, err = s.env.BoolPtr("BLOCK_ADS")
-	if err != nil {
-		return blacklist, err
+		return blacklist, fmt.Errorf("environment variable BLOCK_ADS: %w", err)
 	}

 	blacklist.AddBlockedIPs, blacklist.AddBlockedIPPrefixes,
-		err = s.readDoTPrivateAddresses() // TODO v4 split in 2
+		err = readDoTPrivateAddresses() // TODO v4 split in 2
 	if err != nil {
 		return blacklist, err
 	}

-	blacklist.AllowedHosts = s.env.CSV("UNBLOCK") // TODO v4 change name
+	blacklist.AllowedHosts = envToCSV("UNBLOCK") // TODO v4 change name

 	return blacklist, nil
 }

+func (s *Source) readBlockSurveillance() (blocked *bool, err error) {
+	key, value := s.getEnvWithRetro("BLOCK_SURVEILLANCE", "BLOCK_NSA")
+	if value == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	blocked = new(bool)
+	*blocked, err = binary.Validate(value)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable %s: %w", key, err)
+	}
+
+	return blocked, nil
+}
+
 var (
 	ErrPrivateAddressNotValid = errors.New("private address is not a valid IP or CIDR range")
 )

-func (s *Source) readDoTPrivateAddresses() (ips []netip.Addr,
+func readDoTPrivateAddresses() (ips []netip.Addr,
 	ipPrefixes []netip.Prefix, err error) {
-	privateAddresses := s.env.CSV("DOT_PRIVATE_ADDRESS")
+	privateAddresses := envToCSV("DOT_PRIVATE_ADDRESS")
 	if len(privateAddresses) == 0 {
 		return nil, nil, nil
 	}
--- a/internal/configuration/sources/env/dot.go
+++ b/internal/configuration/sources/env/dot.go
@@ -1,21 +1,23 @@
 package env

 import (
+	"fmt"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

 func (s *Source) readDoT() (dot settings.DoT, err error) {
-	dot.Enabled, err = s.env.BoolPtr("DOT")
+	dot.Enabled, err = envToBoolPtr("DOT")
 	if err != nil {
-		return dot, err
+		return dot, fmt.Errorf("environment variable DOT: %w", err)
 	}

-	dot.UpdatePeriod, err = s.env.DurationPtr("DNS_UPDATE_PERIOD")
+	dot.UpdatePeriod, err = envToDurationPtr("DNS_UPDATE_PERIOD")
 	if err != nil {
-		return dot, err
+		return dot, fmt.Errorf("environment variable DNS_UPDATE_PERIOD: %w", err)
 	}

-	dot.Unbound, err = s.readUnbound()
+	dot.Unbound, err = readUnbound()
 	if err != nil {
 		return dot, err
 	}
--- a/internal/configuration/sources/env/firewall.go
+++ b/internal/configuration/sources/env/firewall.go
@@ -1,36 +1,80 @@
 package env

 import (
+	"errors"
+	"fmt"
+	"net/netip"
+	"strconv"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

 func (s *Source) readFirewall() (firewall settings.Firewall, err error) {
-	firewall.VPNInputPorts, err = s.env.CSVUint16("FIREWALL_VPN_INPUT_PORTS")
+	vpnInputPortStrings := envToCSV("FIREWALL_VPN_INPUT_PORTS")
+	firewall.VPNInputPorts, err = stringsToPorts(vpnInputPortStrings)
 	if err != nil {
-		return firewall, err
+		return firewall, fmt.Errorf("environment variable FIREWALL_VPN_INPUT_PORTS: %w", err)
 	}

-	firewall.InputPorts, err = s.env.CSVUint16("FIREWALL_INPUT_PORTS")
+	inputPortStrings := envToCSV("FIREWALL_INPUT_PORTS")
+	firewall.InputPorts, err = stringsToPorts(inputPortStrings)
 	if err != nil {
-		return firewall, err
+		return firewall, fmt.Errorf("environment variable FIREWALL_INPUT_PORTS: %w", err)
 	}

-	firewall.OutboundSubnets, err = s.env.CSVNetipPrefixes("FIREWALL_OUTBOUND_SUBNETS",
-		env.RetroKeys("EXTRA_SUBNETS"))
+	outboundSubnetsKey, _ := s.getEnvWithRetro("FIREWALL_OUTBOUND_SUBNETS", "EXTRA_SUBNETS")
+	outboundSubnetStrings := envToCSV(outboundSubnetsKey)
+	firewall.OutboundSubnets, err = stringsToNetipPrefixes(outboundSubnetStrings)
 	if err != nil {
-		return firewall, err
+		return firewall, fmt.Errorf("environment variable %s: %w", outboundSubnetsKey, err)
 	}

-	firewall.Enabled, err = s.env.BoolPtr("FIREWALL")
+	firewall.Enabled, err = envToBoolPtr("FIREWALL")
 	if err != nil {
-		return firewall, err
+		return firewall, fmt.Errorf("environment variable FIREWALL: %w", err)
 	}

-	firewall.Debug, err = s.env.BoolPtr("FIREWALL_DEBUG")
+	firewall.Debug, err = envToBoolPtr("FIREWALL_DEBUG")
 	if err != nil {
-		return firewall, err
+		return firewall, fmt.Errorf("environment variable FIREWALL_DEBUG: %w", err)
 	}

 	return firewall, nil
 }
+
+var (
+	ErrPortParsing = errors.New("cannot parse port")
+	ErrPortValue   = errors.New("port value is not valid")
+)
+
+func stringsToPorts(ss []string) (ports []uint16, err error) {
+	if len(ss) == 0 {
+		return nil, nil
+	}
+	ports = make([]uint16, len(ss))
+	for i, s := range ss {
+		port, err := strconv.Atoi(s)
+		if err != nil {
+			return nil, fmt.Errorf("%w: %s: %s", ErrPortParsing, s, err)
+		} else if port < 1 || port > 65535 {
+			return nil, fmt.Errorf("%w: must be between 1 and 65535: %d",
+				ErrPortValue, port)
+		}
+		ports[i] = uint16(port)
+	}
+	return ports, nil
+}
+
+func stringsToNetipPrefixes(ss []string) (ipPrefixes []netip.Prefix, err error) {
+	if len(ss) == 0 {
+		return nil, nil
+	}
+	ipPrefixes = make([]netip.Prefix, len(ss))
+	for i, s := range ss {
+		ipPrefixes[i], err = netip.ParsePrefix(s)
+		if err != nil {
+			return nil, fmt.Errorf("parsing IP network %q: %w", s, err)
+		}
+	}
+	return ipPrefixes, nil
+}
--- a/internal/configuration/sources/env/health.go
+++ b/internal/configuration/sources/env/health.go
@@ -1,35 +1,51 @@
 package env

 import (
+	"fmt"
+	"time"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

 func (s *Source) ReadHealth() (health settings.Health, err error) {
-	health.ServerAddress = s.env.String("HEALTH_SERVER_ADDRESS")
-	health.TargetAddress = s.env.String("HEALTH_TARGET_ADDRESS",
-		env.RetroKeys("HEALTH_ADDRESS_TO_PING"))
+	health.ServerAddress = getCleanedEnv("HEALTH_SERVER_ADDRESS")
+	_, health.TargetAddress = s.getEnvWithRetro("HEALTH_TARGET_ADDRESS", "HEALTH_ADDRESS_TO_PING")

-	successWaitPtr, err := s.env.DurationPtr("HEALTH_SUCCESS_WAIT_DURATION")
+	successWaitPtr, err := envToDurationPtr("HEALTH_SUCCESS_WAIT_DURATION")
 	if err != nil {
-		return health, err
+		return health, fmt.Errorf("environment variable HEALTH_SUCCESS_WAIT_DURATION: %w", err)
 	} else if successWaitPtr != nil {
 		health.SuccessWait = *successWaitPtr
 	}

-	health.VPN.Initial, err = s.env.DurationPtr(
+	health.VPN.Initial, err = s.readDurationWithRetro(
 		"HEALTH_VPN_DURATION_INITIAL",
-		env.RetroKeys("HEALTH_OPENVPN_DURATION_INITIAL"))
+		"HEALTH_OPENVPN_DURATION_INITIAL")
 	if err != nil {
 		return health, err
 	}

-	health.VPN.Addition, err = s.env.DurationPtr(
+	health.VPN.Addition, err = s.readDurationWithRetro(
 		"HEALTH_VPN_DURATION_ADDITION",
-		env.RetroKeys("HEALTH_OPENVPN_DURATION_ADDITION"))
+		"HEALTH_OPENVPN_DURATION_ADDITION")
 	if err != nil {
 		return health, err
 	}

 	return health, nil
 }
+
+func (s *Source) readDurationWithRetro(envKey, retroEnvKey string) (d *time.Duration, err error) {
+	envKey, value := s.getEnvWithRetro(envKey, retroEnvKey)
+	if value == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	d = new(time.Duration)
+	*d, err = time.ParseDuration(value)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable %s: %w", envKey, err)
+	}
+
+	return d, nil
+}
--- a/internal/configuration/sources/env/helpers.go
+++ b/internal/configuration/sources/env/helpers.go
@@ -3,10 +3,127 @@ package env
 import (
 	"fmt"
 	"os"
+	"strconv"
+	"strings"
+	"time"

-	"github.com/qdm12/gosettings/sources/env"
+	"github.com/qdm12/govalid/binary"
+	"github.com/qdm12/govalid/integer"
 )

+// getCleanedEnv returns an environment variable value with
+// surrounding spaces and trailing new line characters removed.
+func getCleanedEnv(envKey string) (value string) {
+	value = os.Getenv(envKey)
+	value = strings.TrimSpace(value)
+	value = strings.TrimSuffix(value, "\r\n")
+	value = strings.TrimSuffix(value, "\n")
+	return value
+}
+
+func envToCSV(envKey string) (values []string) {
+	csv := getCleanedEnv(envKey)
+	if csv == "" {
+		return nil
+	}
+	return lowerAndSplit(csv)
+}
+
+func envToFloat64(envKey string) (f float64, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return 0, nil
+	}
+	const bits = 64
+	return strconv.ParseFloat(s, bits)
+}
+
+func envToStringPtr(envKey string) (stringPtr *string) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return nil
+	}
+	return &s
+}
+
+func envToBoolPtr(envKey string) (boolPtr *bool, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+	value, err := binary.Validate(s)
+	if err != nil {
+		return nil, err
+	}
+	return &value, nil
+}
+
+func envToIntPtr(envKey string) (intPtr *int, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+	value, err := strconv.Atoi(s)
+	if err != nil {
+		return nil, err
+	}
+	return &value, nil
+}
+
+func envToUint8Ptr(envKey string) (uint8Ptr *uint8, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	const min, max = 0, 255
+	value, err := integer.Validate(s, integer.OptionRange(min, max))
+	if err != nil {
+		return nil, err
+	}
+
+	uint8Ptr = new(uint8)
+	*uint8Ptr = uint8(value)
+	return uint8Ptr, nil
+}
+
+func envToUint16Ptr(envKey string) (uint16Ptr *uint16, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	const min, max = 0, 65535
+	value, err := integer.Validate(s, integer.OptionRange(min, max))
+	if err != nil {
+		return nil, err
+	}
+
+	uint16Ptr = new(uint16)
+	*uint16Ptr = uint16(value)
+	return uint16Ptr, nil
+}
+
+func envToDurationPtr(envKey string) (durationPtr *time.Duration, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	durationPtr = new(time.Duration)
+	*durationPtr, err = time.ParseDuration(s)
+	if err != nil {
+		return nil, err
+	}
+
+	return durationPtr, nil
+}
+
+func lowerAndSplit(csv string) (values []string) {
+	csv = strings.ToLower(csv)
+	return strings.Split(csv, ",")
+}
+
 func unsetEnvKeys(envKeys []string, err error) (newErr error) {
 	newErr = err
 	for _, envKey := range envKeys {
@@ -18,16 +135,6 @@ func unsetEnvKeys(envKeys []string, err error) (newErr error) {
 	return newErr
 }

-func ptrTo[T any](value T) *T {
-	return &value
-}
-
-func firstKeySet(e env.Env, keys ...string) (firstKeySet string) {
-	for _, key := range keys {
-		value := e.Get(key)
-		if value != nil {
-			return key
-		}
-	}
-	return ""
-}
+func stringPtr(s string) *string { return &s }
+func uint32Ptr(n uint32) *uint32 { return &n }
+func boolPtr(b bool) *bool       { return &b }
--- a/internal/configuration/sources/env/helpers_test.go
+++ b/internal/configuration/sources/env/helpers_test.go
@@ -0,0 +1,22 @@
+package env
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// setTestEnv is used to set environment variables in
+// parallel tests.
+func setTestEnv(t *testing.T, key, value string) {
+	t.Helper()
+	existing := os.Getenv(key)
+	err := os.Setenv(key, value) //nolint:tenv
+	t.Cleanup(func() {
+		err = os.Setenv(key, existing)
+		assert.NoError(t, err)
+	})
+	require.NoError(t, err)
+}
--- a/internal/configuration/sources/env/httproxy.go
+++ b/internal/configuration/sources/env/httproxy.go
@@ -4,32 +4,22 @@ import (
 	"fmt"

 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 	"github.com/qdm12/govalid/binary"
 )

 func (s *Source) readHTTPProxy() (httpProxy settings.HTTPProxy, err error) {
-	httpProxy.User = s.env.Get("HTTPPROXY_USER",
-		env.RetroKeys("PROXY_USER", "TINYPROXY_USER"),
-		env.ForceLowercase(false))
+	httpProxy.User = s.readHTTProxyUser()
+	httpProxy.Password = s.readHTTProxyPassword()
+	httpProxy.ListeningAddress = s.readHTTProxyListeningAddress()

-	httpProxy.Password = s.env.Get("HTTPPROXY_PASSWORD",
-		env.RetroKeys("PROXY_PASSWORD", "TINYPROXY_PASSWORD"),
-		env.ForceLowercase(false))
-
-	httpProxy.ListeningAddress, err = s.readHTTProxyListeningAddress()
+	httpProxy.Enabled, err = s.readHTTProxyEnabled()
 	if err != nil {
 		return httpProxy, err
 	}

-	httpProxy.Enabled, err = s.env.BoolPtr("HTTPPROXY", env.RetroKeys("PROXY", "TINYPROXY"))
+	httpProxy.Stealth, err = envToBoolPtr("HTTPPROXY_STEALTH")
 	if err != nil {
-		return httpProxy, err
-	}
-
-	httpProxy.Stealth, err = s.env.BoolPtr("HTTPPROXY_STEALTH")
-	if err != nil {
-		return httpProxy, err
+		return httpProxy, fmt.Errorf("environment variable HTTPPROXY_STEALTH: %w", err)
 	}

 	httpProxy.Log, err = s.readHTTProxyLog()
@@ -40,42 +30,59 @@ func (s *Source) readHTTPProxy() (httpProxy settings.HTTPProxy, err error) {
 	return httpProxy, nil
 }

-func (s *Source) readHTTProxyListeningAddress() (listeningAddress string, err error) {
-	const currentKey = "HTTPPROXY_LISTENING_ADDRESS"
-	key := firstKeySet(s.env, "HTTPPROXY_PORT", "TINYPROXY_PORT", "PROXY_PORT",
-		currentKey)
-	switch key {
-	case "":
-		return "", nil
-	case currentKey:
-		return s.env.String(key), nil
+func (s *Source) readHTTProxyUser() (user *string) {
+	_, value := s.getEnvWithRetro("HTTPPROXY_USER", "PROXY_USER", "TINYPROXY_USER")
+	if value != "" {
+		return &value
 	}
-
-	// Retro-compatible keys using a port only
-	s.handleDeprecatedKey(key, currentKey)
-	port, err := s.env.Uint16Ptr(key)
-	if err != nil {
-		return "", err
-	}
-	return fmt.Sprintf(":%d", *port), nil
+	return nil
 }

-func (s *Source) readHTTProxyLog() (enabled *bool, err error) {
-	const currentKey = "HTTPPROXY_LOG"
-	key := firstKeySet(s.env, "PROXY_LOG", "TINYPROXY_LOG", "HTTPPROXY_LOG")
-	switch key {
-	case "":
+func (s *Source) readHTTProxyPassword() (user *string) {
+	_, value := s.getEnvWithRetro("HTTPPROXY_PASSWORD", "PROXY_PASSWORD", "TINYPROXY_PASSWORD")
+	if value != "" {
+		return &value
+	}
+	return nil
+}
+
+func (s *Source) readHTTProxyListeningAddress() (listeningAddress string) {
+	key, value := s.getEnvWithRetro("HTTPPROXY_LISTENING_ADDRESS", "PROXY_PORT", "TINYPROXY_PORT", "HTTPPROXY_PORT")
+	if key == "HTTPPROXY_LISTENING_ADDRESS" {
+		return value
+	}
+	return ":" + value
+}
+
+func (s *Source) readHTTProxyEnabled() (enabled *bool, err error) {
+	key, value := s.getEnvWithRetro("HTTPPROXY", "PROXY", "TINYPROXY")
+	if value == "" {
 		return nil, nil //nolint:nilnil
-	case currentKey:
-		return s.env.BoolPtr(key)
 	}

-	// Retro-compatible keys using different boolean verbs
-	s.handleDeprecatedKey(key, currentKey)
-	value := s.env.String(key)
-	retroOption := binary.OptionEnabled("on", "info", "connect", "notice")
-
-	enabled, err = binary.Validate(value, retroOption)
+	enabled = new(bool)
+	*enabled, err = binary.Validate(value)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable %s: %w", key, err)
+	}
+
+	return enabled, nil
+}
+
+func (s *Source) readHTTProxyLog() (enabled *bool, err error) {
+	key, value := s.getEnvWithRetro("HTTPPROXY_LOG", "PROXY_LOG_LEVEL", "TINYPROXY_LOG")
+	if value == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	var binaryOptions []binary.Option
+	if key != "HTTPROXY_LOG" {
+		retroOption := binary.OptionEnabled("on", "info", "connect", "notice")
+		binaryOptions = append(binaryOptions, retroOption)
+	}
+
+	enabled = new(bool)
+	*enabled, err = binary.Validate(value, binaryOptions...)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable %s: %w", key, err)
 	}
--- a/internal/configuration/sources/env/log.go
+++ b/internal/configuration/sources/env/log.go
@@ -9,8 +9,8 @@ import (
 	"github.com/qdm12/log"
 )

-func (s *Source) readLog() (log settings.Log, err error) {
-	log.Level, err = s.readLogLevel()
+func readLog() (log settings.Log, err error) {
+	log.Level, err = readLogLevel()
 	if err != nil {
 		return log, err
 	}
@@ -18,14 +18,14 @@ func (s *Source) readLog() (log settings.Log, err error) {
 	return log, nil
 }

-func (s *Source) readLogLevel() (level *log.Level, err error) {
-	value := s.env.String("LOG_LEVEL")
-	if value == "" {
+func readLogLevel() (level *log.Level, err error) {
+	s := getCleanedEnv("LOG_LEVEL")
+	if s == "" {
 		return nil, nil //nolint:nilnil
 	}

 	level = new(log.Level)
-	*level, err = parseLogLevel(value)
+	*level, err = parseLogLevel(s)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable LOG_LEVEL: %w", err)
 	}
--- a/internal/configuration/sources/env/openvpn.go
+++ b/internal/configuration/sources/env/openvpn.go
@@ -1,10 +1,11 @@
 package env

 import (
+	"fmt"
 	"strings"

 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
+	"github.com/qdm12/govalid/binary"
 )

 func (s *Source) readOpenVPN() (
@@ -14,64 +15,113 @@ func (s *Source) readOpenVPN() (
 			"OPENVPN_KEY_PASSPHRASE", "OPENVPN_ENCRYPTED_KEY"}, err)
 	}()

-	openVPN.Version = s.env.String("OPENVPN_VERSION")
-	openVPN.User = s.env.Get("OPENVPN_USER",
-		env.RetroKeys("USER"), env.ForceLowercase(false))
-	openVPN.Password = s.env.Get("OPENVPN_PASSWORD",
-		env.RetroKeys("PASSWORD"), env.ForceLowercase(false))
-	openVPN.ConfFile = s.env.Get("OPENVPN_CUSTOM_CONFIG", env.ForceLowercase(false))
-	openVPN.Ciphers = s.env.CSV("OPENVPN_CIPHERS", env.RetroKeys("OPENVPN_CIPHER"))
-	openVPN.Auth = s.env.Get("OPENVPN_AUTH")
-	openVPN.Cert = s.env.Get("OPENVPN_CERT", env.ForceLowercase(false))
-	openVPN.Key = s.env.Get("OPENVPN_KEY", env.ForceLowercase(false))
-	openVPN.EncryptedKey = s.env.Get("OPENVPN_ENCRYPTED_KEY", env.ForceLowercase(false))
-	openVPN.KeyPassphrase = s.env.Get("OPENVPN_KEY_PASSPHRASE", env.ForceLowercase(false))
+	openVPN.Version = getCleanedEnv("OPENVPN_VERSION")
+	openVPN.User = s.readOpenVPNUser()
+	openVPN.Password = s.readOpenVPNPassword()
+	confFile := getCleanedEnv("OPENVPN_CUSTOM_CONFIG")
+	if confFile != "" {
+		openVPN.ConfFile = &confFile
+	}
+
+	ciphersKey, _ := s.getEnvWithRetro("OPENVPN_CIPHERS", "OPENVPN_CIPHER")
+	openVPN.Ciphers = envToCSV(ciphersKey)
+
+	auth := getCleanedEnv("OPENVPN_AUTH")
+	if auth != "" {
+		openVPN.Auth = &auth
+	}
+
+	openVPN.Cert = envToStringPtr("OPENVPN_CERT")
+	openVPN.Key = envToStringPtr("OPENVPN_KEY")
+	openVPN.EncryptedKey = envToStringPtr("OPENVPN_ENCRYPTED_KEY")
+
+	openVPN.KeyPassphrase = s.readOpenVPNKeyPassphrase()

 	openVPN.PIAEncPreset = s.readPIAEncryptionPreset()

-	openVPN.MSSFix, err = s.env.Uint16Ptr("OPENVPN_MSSFIX")
+	openVPN.MSSFix, err = envToUint16Ptr("OPENVPN_MSSFIX")
 	if err != nil {
-		return openVPN, err
+		return openVPN, fmt.Errorf("environment variable OPENVPN_MSSFIX: %w", err)
 	}

-	openVPN.Interface = s.env.String("VPN_INTERFACE",
-		env.RetroKeys("OPENVPN_INTERFACE"), env.ForceLowercase(false))
+	_, openVPN.Interface = s.getEnvWithRetro("VPN_INTERFACE", "OPENVPN_INTERFACE")

 	openVPN.ProcessUser, err = s.readOpenVPNProcessUser()
 	if err != nil {
 		return openVPN, err
 	}

-	openVPN.Verbosity, err = s.env.IntPtr("OPENVPN_VERBOSITY")
+	openVPN.Verbosity, err = envToIntPtr("OPENVPN_VERBOSITY")
 	if err != nil {
-		return openVPN, err
+		return openVPN, fmt.Errorf("environment variable OPENVPN_VERBOSITY: %w", err)
 	}

-	flagsPtr := s.env.Get("OPENVPN_FLAGS", env.ForceLowercase(false))
-	if flagsPtr != nil {
-		openVPN.Flags = strings.Fields(*flagsPtr)
+	flagsStr := getCleanedEnv("OPENVPN_FLAGS")
+	if flagsStr != "" {
+		openVPN.Flags = strings.Fields(flagsStr)
 	}

 	return openVPN, nil
 }

+func (s *Source) readOpenVPNUser() (user *string) {
+	user = new(string)
+	_, *user = s.getEnvWithRetro("OPENVPN_USER", "USER")
+	if *user == "" {
+		return nil
+	}
+
+	// Remove spaces in user ID to simplify user's life, thanks @JeordyR
+	*user = strings.ReplaceAll(*user, " ", "")
+	return user
+}
+
+func (s *Source) readOpenVPNPassword() (password *string) {
+	password = new(string)
+	_, *password = s.getEnvWithRetro("OPENVPN_PASSWORD", "PASSWORD")
+	if *password == "" {
+		return nil
+	}
+
+	return password
+}
+
+func (s *Source) readOpenVPNKeyPassphrase() (passphrase *string) {
+	passphrase = new(string)
+	*passphrase = getCleanedEnv("OPENVPN_KEY_PASSPHRASE")
+	if *passphrase == "" {
+		return nil
+	}
+	return passphrase
+}
+
 func (s *Source) readPIAEncryptionPreset() (presetPtr *string) {
-	return s.env.Get(
+	_, preset := s.getEnvWithRetro(
 		"PRIVATE_INTERNET_ACCESS_OPENVPN_ENCRYPTION_PRESET",
-		env.RetroKeys("ENCRYPTION", "PIA_ENCRYPTION"))
+		"PIA_ENCRYPTION", "ENCRYPTION")
+	if preset != "" {
+		return &preset
+	}
+	return nil
 }

 func (s *Source) readOpenVPNProcessUser() (processUser string, err error) {
-	value, err := s.env.BoolPtr("OPENVPN_ROOT") // Retro-compatibility
-	if err != nil {
-		return "", err
-	} else if value != nil {
-		if *value {
-			return "root", nil
-		}
-		const defaultNonRootUser = "nonrootuser"
-		return defaultNonRootUser, nil
+	key, value := s.getEnvWithRetro("OPENVPN_PROCESS_USER", "OPENVPN_ROOT")
+	if key == "OPENVPN_PROCESS_USER" {
+		return value, nil
 	}

-	return s.env.String("OPENVPN_PROCESS_USER"), nil
+	// Retro-compatibility
+	if value == "" {
+		return "", nil
+	}
+	root, err := binary.Validate(value)
+	if err != nil {
+		return "", fmt.Errorf("environment variable %s: %w", key, err)
+	}
+	if root {
+		return "root", nil
+	}
+	const defaultNonRootUser = "nonrootuser"
+	return defaultNonRootUser, nil
 }
--- a/internal/configuration/sources/env/openvpnselection.go
+++ b/internal/configuration/sources/env/openvpnselection.go
@@ -7,20 +7,22 @@ import (

 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/constants"
-	"github.com/qdm12/gosettings/sources/env"
+	"github.com/qdm12/govalid/port"
 )

 func (s *Source) readOpenVPNSelection() (
 	selection settings.OpenVPNSelection, err error) {
-	selection.ConfFile = s.env.Get("OPENVPN_CUSTOM_CONFIG", env.ForceLowercase(false))
+	confFile := getCleanedEnv("OPENVPN_CUSTOM_CONFIG")
+	if confFile != "" {
+		selection.ConfFile = &confFile
+	}

 	selection.TCP, err = s.readOpenVPNProtocol()
 	if err != nil {
 		return selection, err
 	}

-	selection.CustomPort, err = s.env.Uint16Ptr("VPN_ENDPOINT_PORT",
-		env.RetroKeys("PORT", "OPENVPN_PORT"))
+	selection.CustomPort, err = s.readOpenVPNCustomPort()
 	if err != nil {
 		return selection, err
 	}
@@ -33,24 +35,32 @@ func (s *Source) readOpenVPNSelection() (
 var ErrOpenVPNProtocolNotValid = errors.New("OpenVPN protocol is not valid")

 func (s *Source) readOpenVPNProtocol() (tcp *bool, err error) {
-	const currentKey = "OPENVPN_PROTOCOL"
-	envKey := firstKeySet(s.env, "PROTOCOL", currentKey)
-	switch envKey {
+	envKey, protocol := s.getEnvWithRetro("OPENVPN_PROTOCOL", "PROTOCOL")
+
+	switch strings.ToLower(protocol) {
 	case "":
 		return nil, nil //nolint:nilnil
-	case currentKey:
-	default: // Retro compatibility
-		s.handleDeprecatedKey(envKey, currentKey)
-	}
-
-	protocol := s.env.String(envKey)
-	switch strings.ToLower(protocol) {
 	case constants.UDP:
-		return ptrTo(false), nil
+		return boolPtr(false), nil
 	case constants.TCP:
-		return ptrTo(true), nil
+		return boolPtr(true), nil
 	default:
 		return nil, fmt.Errorf("environment variable %s: %w: %s",
 			envKey, ErrOpenVPNProtocolNotValid, protocol)
 	}
 }
+
+func (s *Source) readOpenVPNCustomPort() (customPort *uint16, err error) {
+	key, value := s.getEnvWithRetro("VPN_ENDPOINT_PORT", "PORT", "OPENVPN_PORT")
+	if value == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	customPort = new(uint16)
+	*customPort, err = port.Validate(value)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable %s: %w", key, err)
+	}
+
+	return customPort, nil
+}
--- a/internal/configuration/sources/env/portforward.go
+++ b/internal/configuration/sources/env/portforward.go
@@ -1,27 +1,29 @@
 package env

 import (
+	"fmt"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

 func (s *Source) readPortForward() (
 	portForwarding settings.PortForwarding, err error) {
-	portForwarding.Enabled, err = s.env.BoolPtr("VPN_PORT_FORWARDING",
-		env.RetroKeys(
-			"PORT_FORWARDING",
-			"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING",
-		))
+	key, _ := s.getEnvWithRetro(
+		"VPN_PORT_FORWARDING",
+		"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING",
+		"PORT_FORWARDING")
+	portForwarding.Enabled, err = envToBoolPtr(key)
 	if err != nil {
-		return portForwarding, err
+		return portForwarding, fmt.Errorf("environment variable %s: %w", key, err)
 	}

-	portForwarding.Filepath = s.env.Get("VPN_PORT_FORWARDING_STATUS_FILE",
-		env.ForceLowercase(false),
-		env.RetroKeys(
-			"PORT_FORWARDING_STATUS_FILE",
-			"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING_STATUS_FILE",
-		))
+	_, value := s.getEnvWithRetro(
+		"VPN_PORT_FORWARDING_STATUS_FILE",
+		"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING_STATUS_FILE",
+		"PORT_FORWARDING_STATUS_FILE")
+	if value != "" {
+		portForwarding.Filepath = stringPtr(value)
+	}

 	return portForwarding, nil
 }
--- a/internal/configuration/sources/env/pprof.go
+++ b/internal/configuration/sources/env/pprof.go
@@ -1,26 +1,28 @@
 package env

 import (
+	"fmt"
+
 	"github.com/qdm12/gluetun/internal/pprof"
 )

-func (s *Source) readPprof() (settings pprof.Settings, err error) {
-	settings.Enabled, err = s.env.BoolPtr("PPROF_ENABLED")
+func readPprof() (settings pprof.Settings, err error) {
+	settings.Enabled, err = envToBoolPtr("PPROF_ENABLED")
 	if err != nil {
-		return settings, err
+		return settings, fmt.Errorf("environment variable PPROF_ENABLED: %w", err)
 	}

-	settings.BlockProfileRate, err = s.env.IntPtr("PPROF_BLOCK_PROFILE_RATE")
+	settings.BlockProfileRate, err = envToIntPtr("PPROF_BLOCK_PROFILE_RATE")
 	if err != nil {
-		return settings, err
+		return settings, fmt.Errorf("environment variable PPROF_BLOCK_PROFILE_RATE: %w", err)
 	}

-	settings.MutexProfileRate, err = s.env.IntPtr("PPROF_MUTEX_PROFILE_RATE")
+	settings.MutexProfileRate, err = envToIntPtr("PPROF_MUTEX_PROFILE_RATE")
 	if err != nil {
-		return settings, err
+		return settings, fmt.Errorf("environment variable PPROF_MUTEX_PROFILE_RATE: %w", err)
 	}

-	settings.HTTPServer.Address = s.env.String("PPROF_HTTP_SERVER_ADDRESS")
+	settings.HTTPServer.Address = getCleanedEnv("PPROF_HTTP_SERVER_ADDRESS")

 	return settings, nil
 }
--- a/internal/configuration/sources/env/provider.go
+++ b/internal/configuration/sources/env/provider.go
@@ -7,7 +7,6 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/constants/vpn"
-	"github.com/qdm12/gosettings/sources/env"
 )

 func (s *Source) readProvider(vpnType string) (provider settings.Provider, err error) {
@@ -31,20 +30,19 @@ func (s *Source) readProvider(vpnType string) (provider settings.Provider, err e
 }

 func (s *Source) readVPNServiceProvider(vpnType string) (vpnProviderPtr *string) {
-	valuePtr := s.env.Get("VPN_SERVICE_PROVIDER", env.RetroKeys("VPNSP"))
-	if valuePtr == nil {
-		if vpnType != vpn.Wireguard && s.env.Get("OPENVPN_CUSTOM_CONFIG") != nil {
+	_, value := s.getEnvWithRetro("VPN_SERVICE_PROVIDER", "VPNSP")
+	if value == "" {
+		if vpnType != vpn.Wireguard && getCleanedEnv("OPENVPN_CUSTOM_CONFIG") != "" {
 			// retro compatibility
-			return ptrTo(providers.Custom)
+			return stringPtr(providers.Custom)
 		}
 		return nil
 	}

-	value := *valuePtr
 	value = strings.ToLower(value)
 	if value == "pia" { // retro compatibility
-		return ptrTo(providers.PrivateInternetAccess)
+		return stringPtr(providers.PrivateInternetAccess)
 	}

-	return ptrTo(value)
+	return stringPtr(value)
 }
--- a/internal/configuration/sources/env/publicip.go
+++ b/internal/configuration/sources/env/publicip.go
@@ -1,18 +1,42 @@
 package env

 import (
+	"fmt"
+	"time"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

 func (s *Source) readPublicIP() (publicIP settings.PublicIP, err error) {
-	publicIP.Period, err = s.env.DurationPtr("PUBLICIP_PERIOD")
+	publicIP.Period, err = readPublicIPPeriod()
 	if err != nil {
 		return publicIP, err
 	}

-	publicIP.IPFilepath = s.env.Get("PUBLICIP_FILE",
-		env.ForceLowercase(false), env.RetroKeys("IP_STATUS_FILE"))
+	publicIP.IPFilepath = s.readPublicIPFilepath()

 	return publicIP, nil
 }
+
+func readPublicIPPeriod() (period *time.Duration, err error) {
+	s := getCleanedEnv("PUBLICIP_PERIOD")
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	period = new(time.Duration)
+	*period, err = time.ParseDuration(s)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable PUBLICIP_PERIOD: %w", err)
+	}
+
+	return period, nil
+}
+
+func (s *Source) readPublicIPFilepath() (filepath *string) {
+	_, value := s.getEnvWithRetro("PUBLICIP_FILE", "IP_STATUS_FILE")
+	if value != "" {
+		return &value
+	}
+	return nil
+}
--- a/internal/configuration/sources/env/reader.go
+++ b/internal/configuration/sources/env/reader.go
@@ -1,16 +1,11 @@
 package env

 import (
-	"os"
-
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

 type Source struct {
-	env                 env.Env
-	warner              Warner
-	handleDeprecatedKey func(deprecatedKey, newKey string)
+	warner Warner
 }

 type Warner interface {
@@ -18,16 +13,8 @@ type Warner interface {
 }

 func New(warner Warner) *Source {
-	handleDeprecatedKey := func(deprecatedKey, newKey string) {
-		warner.Warn(
-			"You are using the old environment variable " + deprecatedKey +
-				", please consider changing it to " + newKey)
-	}
-
 	return &Source{
-		env:                 *env.New(os.Environ(), handleDeprecatedKey),
-		warner:              warner,
-		handleDeprecatedKey: handleDeprecatedKey,
+		warner: warner,
 	}
 }

@@ -59,7 +46,7 @@ func (s *Source) Read() (settings settings.Settings, err error) {
 		return settings, err
 	}

-	settings.Log, err = s.readLog()
+	settings.Log, err = readLog()
 	if err != nil {
 		return settings, err
 	}
@@ -69,12 +56,12 @@ func (s *Source) Read() (settings settings.Settings, err error) {
 		return settings, err
 	}

-	settings.Updater, err = s.readUpdater()
+	settings.Updater, err = readUpdater()
 	if err != nil {
 		return settings, err
 	}

-	settings.Version, err = s.readVersion()
+	settings.Version, err = readVersion()
 	if err != nil {
 		return settings, err
 	}
@@ -94,10 +81,37 @@ func (s *Source) Read() (settings settings.Settings, err error) {
 		return settings, err
 	}

-	settings.Pprof, err = s.readPprof()
+	settings.Pprof, err = readPprof()
 	if err != nil {
 		return settings, err
 	}

 	return settings, nil
 }
+
+func (s *Source) onRetroActive(oldKey, newKey string) {
+	s.warner.Warn(
+		"You are using the old environment variable " + oldKey +
+			", please consider changing it to " + newKey)
+}
+
+// getEnvWithRetro returns the first environment variable
+// key and corresponding non empty value from the environment
+// variable keys given. It first goes through the retroKeys
+// and end on returning the value corresponding to the currentKey.
+// Note retroKeys should be in order from oldest to most
+// recent retro-compatibility key.
+func (s *Source) getEnvWithRetro(currentKey string,
+	retroKeys ...string) (key, value string) {
+	// We check retro-compatibility keys first since
+	// the current key might be set in the Dockerfile.
+	for _, key = range retroKeys {
+		value = getCleanedEnv(key)
+		if value != "" {
+			s.onRetroActive(key, currentKey)
+			return key, value
+		}
+	}
+
+	return currentKey, getCleanedEnv(currentKey)
+}
--- a/internal/configuration/sources/env/server.go
+++ b/internal/configuration/sources/env/server.go
@@ -1,11 +1,14 @@
 package env

 import (
+	"fmt"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/govalid/binary"
 )

 func (s *Source) readControlServer() (controlServer settings.ControlServer, err error) {
-	controlServer.Log, err = s.env.BoolPtr("HTTP_CONTROL_SERVER_LOG")
+	controlServer.Log, err = readControlServerLog()
 	if err != nil {
 		return controlServer, err
 	}
@@ -15,17 +18,31 @@ func (s *Source) readControlServer() (controlServer settings.ControlServer, err
 	return controlServer, nil
 }

-func (s *Source) readControlServerAddress() (address *string) {
-	const currentKey = "HTTP_CONTROL_SERVER_ADDRESS"
-	key := firstKeySet(s.env, "CONTROL_SERVER_ADDRESS", currentKey)
-	if key == currentKey {
-		return s.env.Get(key)
+func readControlServerLog() (enabled *bool, err error) {
+	s := getCleanedEnv("HTTP_CONTROL_SERVER_LOG")
+	if s == "" {
+		return nil, nil //nolint:nilnil
 	}

-	s.handleDeprecatedKey(key, currentKey)
-	value := s.env.Get("CONTROL_SERVER_ADDRESS")
-	if value == nil {
+	log, err := binary.Validate(s)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable HTTP_CONTROL_SERVER_LOG: %w", err)
+	}
+
+	return &log, nil
+}
+
+func (s *Source) readControlServerAddress() (address *string) {
+	key, value := s.getEnvWithRetro("HTTP_CONTROL_SERVER_ADDRESS", "HTTP_CONTROL_SERVER_PORT")
+	if value == "" {
 		return nil
 	}
-	return ptrTo(":" + *value)
+
+	if key == "HTTP_CONTROL_SERVER_ADDRESS" {
+		return &value
+	}
+
+	address = new(string)
+	*address = ":" + value
+	return address
 }
--- a/internal/configuration/sources/env/serverselection.go
+++ b/internal/configuration/sources/env/serverselection.go
@@ -2,69 +2,98 @@ package env

 import (
 	"errors"
+	"fmt"
+	"net/netip"
+	"strconv"
+	"strings"

 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/constants/providers"
-	"github.com/qdm12/gosettings/sources/env"
+)
+
+var (
+	ErrServerNumberNotValid = errors.New("server number is not valid")
 )

 func (s *Source) readServerSelection(vpnProvider, vpnType string) (
 	ss settings.ServerSelection, err error) {
 	ss.VPN = vpnType

-	ss.TargetIP, err = s.env.NetipAddr("VPN_ENDPOINT_IP",
-		env.RetroKeys("OPENVPN_TARGET_IP"))
+	ss.TargetIP, err = s.readOpenVPNTargetIP()
 	if err != nil {
 		return ss, err
 	}

-	ss.Countries = s.env.CSV("SERVER_COUNTRIES", env.RetroKeys("COUNTRY"))
+	countriesKey, _ := s.getEnvWithRetro("SERVER_COUNTRIES", "COUNTRY")
+	ss.Countries = envToCSV(countriesKey)
 	if vpnProvider == providers.Cyberghost && len(ss.Countries) == 0 {
 		// Retro-compatibility for Cyberghost using the REGION variable
-		ss.Countries = s.env.CSV("REGION")
+		ss.Countries = envToCSV("REGION")
 		if len(ss.Countries) > 0 {
-			s.handleDeprecatedKey("REGION", "SERVER_COUNTRIES")
+			s.onRetroActive("REGION", "SERVER_COUNTRIES")
 		}
 	}

-	ss.Regions = s.env.CSV("SERVER_REGIONS", env.RetroKeys("REGION"))
-	ss.Cities = s.env.CSV("SERVER_CITIES", env.RetroKeys("CITY"))
-	ss.ISPs = s.env.CSV("ISP")
-	ss.Hostnames = s.env.CSV("SERVER_HOSTNAMES", env.RetroKeys("SERVER_HOSTNAME"))
-	ss.Names = s.env.CSV("SERVER_NAMES", env.RetroKeys("SERVER_NAME"))
-	ss.Numbers, err = s.env.CSVUint16("SERVER_NUMBER")
-	if err != nil {
-		return ss, err
+	regionsKey, _ := s.getEnvWithRetro("SERVER_REGIONS", "REGION")
+	ss.Regions = envToCSV(regionsKey)
+
+	citiesKey, _ := s.getEnvWithRetro("SERVER_CITIES", "CITY")
+	ss.Cities = envToCSV(citiesKey)
+
+	ss.ISPs = envToCSV("ISP")
+
+	hostnamesKey, _ := s.getEnvWithRetro("SERVER_HOSTNAMES", "SERVER_HOSTNAME")
+	ss.Hostnames = envToCSV(hostnamesKey)
+
+	serverNamesKey, _ := s.getEnvWithRetro("SERVER_NAMES", "SERVER_NAME")
+	ss.Names = envToCSV(serverNamesKey)
+
+	if csv := getCleanedEnv("SERVER_NUMBER"); csv != "" {
+		numbersStrings := strings.Split(csv, ",")
+		numbers := make([]uint16, len(numbersStrings))
+		for i, numberString := range numbersStrings {
+			const base, bitSize = 10, 16
+			number, err := strconv.ParseInt(numberString, base, bitSize)
+			if err != nil {
+				return ss, fmt.Errorf("%w: %s",
+					ErrServerNumberNotValid, numberString)
+			} else if number < 0 || number > 65535 {
+				return ss, fmt.Errorf("%w: %d must be between 0 and 65535",
+					ErrServerNumberNotValid, number)
+			}
+			numbers[i] = uint16(number)
+		}
+		ss.Numbers = numbers
 	}

 	// Mullvad only
-	ss.OwnedOnly, err = s.env.BoolPtr("OWNED_ONLY", env.RetroKeys("OWNED"))
+	ss.OwnedOnly, err = s.readOwnedOnly()
 	if err != nil {
 		return ss, err
 	}

 	// VPNUnlimited and ProtonVPN only
-	ss.FreeOnly, err = s.env.BoolPtr("FREE_ONLY")
+	ss.FreeOnly, err = envToBoolPtr("FREE_ONLY")
 	if err != nil {
-		return ss, err
+		return ss, fmt.Errorf("environment variable FREE_ONLY: %w", err)
 	}

 	// VPNSecure only
-	ss.PremiumOnly, err = s.env.BoolPtr("PREMIUM_ONLY")
+	ss.PremiumOnly, err = envToBoolPtr("PREMIUM_ONLY")
 	if err != nil {
-		return ss, err
+		return ss, fmt.Errorf("environment variable PREMIUM_ONLY: %w", err)
 	}

 	// VPNUnlimited only
-	ss.MultiHopOnly, err = s.env.BoolPtr("MULTIHOP_ONLY")
+	ss.MultiHopOnly, err = envToBoolPtr("MULTIHOP_ONLY")
 	if err != nil {
-		return ss, err
+		return ss, fmt.Errorf("environment variable MULTIHOP_ONLY: %w", err)
 	}

 	// VPNUnlimited only
-	ss.MultiHopOnly, err = s.env.BoolPtr("STREAM_ONLY")
+	ss.MultiHopOnly, err = envToBoolPtr("STREAM_ONLY")
 	if err != nil {
-		return ss, err
+		return ss, fmt.Errorf("environment variable STREAM_ONLY: %w", err)
 	}

 	ss.OpenVPN, err = s.readOpenVPNSelection()
@@ -83,3 +112,26 @@ func (s *Source) readServerSelection(vpnProvider, vpnType string) (
 var (
 	ErrInvalidIP = errors.New("invalid IP address")
 )
+
+func (s *Source) readOpenVPNTargetIP() (ip netip.Addr, err error) {
+	envKey, value := s.getEnvWithRetro("VPN_ENDPOINT_IP", "OPENVPN_TARGET_IP")
+	if value == "" {
+		return ip, nil
+	}
+
+	ip, err = netip.ParseAddr(value)
+	if err != nil {
+		return ip, fmt.Errorf("environment variable %s: %w", envKey, err)
+	}
+
+	return ip, nil
+}
+
+func (s *Source) readOwnedOnly() (ownedOnly *bool, err error) {
+	envKey, _ := s.getEnvWithRetro("OWNED_ONLY", "OWNED")
+	ownedOnly, err = envToBoolPtr(envKey)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable %s: %w", envKey, err)
+	}
+	return ownedOnly, nil
+}
--- a/internal/configuration/sources/env/shadowsocks.go
+++ b/internal/configuration/sources/env/shadowsocks.go
@@ -2,41 +2,43 @@ package env

 import (
 	"fmt"
+	"strings"

 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

 func (s *Source) readShadowsocks() (shadowsocks settings.Shadowsocks, err error) {
-	shadowsocks.Enabled, err = s.env.BoolPtr("SHADOWSOCKS")
+	shadowsocks.Enabled, err = envToBoolPtr("SHADOWSOCKS")
 	if err != nil {
-		return shadowsocks, err
+		return shadowsocks, fmt.Errorf("environment variable SHADOWSOCKS: %w", err)
 	}

-	shadowsocks.Address, err = s.readShadowsocksAddress()
+	shadowsocks.Address = s.readShadowsocksAddress()
+	shadowsocks.LogAddresses, err = envToBoolPtr("SHADOWSOCKS_LOG")
 	if err != nil {
-		return shadowsocks, err
+		return shadowsocks, fmt.Errorf("environment variable SHADOWSOCKS_LOG: %w", err)
 	}
-	shadowsocks.LogAddresses, err = s.env.BoolPtr("SHADOWSOCKS_LOG")
-	if err != nil {
-		return shadowsocks, err
-	}
-	shadowsocks.CipherName = s.env.String("SHADOWSOCKS_CIPHER",
-		env.RetroKeys("SHADOWSOCKS_METHOD"))
-	shadowsocks.Password = s.env.Get("SHADOWSOCKS_PASSWORD", env.ForceLowercase(false))
+	shadowsocks.CipherName = s.readShadowsocksCipher()
+	shadowsocks.Password = envToStringPtr("SHADOWSOCKS_PASSWORD")

 	return shadowsocks, nil
 }

-func (s *Source) readShadowsocksAddress() (address *string, err error) {
-	const currentKey = "SHADOWSOCKS_LISTENING_ADDRESS"
-	port, err := s.env.Uint16Ptr("SHADOWSOCKS_PORT") // retro-compatibility
-	if err != nil {
-		return nil, err
-	} else if port != nil {
-		s.handleDeprecatedKey("SHADOWSOCKS_PORT", currentKey)
-		return ptrTo(fmt.Sprintf(":%d", *port)), nil
+func (s *Source) readShadowsocksAddress() (address string) {
+	key, value := s.getEnvWithRetro("SHADOWSOCKS_LISTENING_ADDRESS", "SHADOWSOCKS_PORT")
+	if value == "" {
+		return ""
 	}

-	return s.env.Get(currentKey), nil
+	if key == "SHADOWSOCKS_LISTENING_ADDRESS" {
+		return value
+	}
+
+	// Retro-compatibility
+	return ":" + value
+}
+
+func (s *Source) readShadowsocksCipher() (cipher string) {
+	_, cipher = s.getEnvWithRetro("SHADOWSOCKS_CIPHER", "SHADOWSOCKS_METHOD")
+	return strings.ToLower(cipher)
 }
--- a/internal/configuration/sources/env/system.go
+++ b/internal/configuration/sources/env/system.go
@@ -1,22 +1,55 @@
 package env

 import (
+	"errors"
+	"fmt"
+	"strconv"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
+)
+
+var (
+	ErrSystemPUIDNotValid     = errors.New("PUID is not valid")
+	ErrSystemPGIDNotValid     = errors.New("PGID is not valid")
+	ErrSystemTimezoneNotValid = errors.New("timezone is not valid")
 )

 func (s *Source) readSystem() (system settings.System, err error) {
-	system.PUID, err = s.env.Uint32Ptr("PUID", env.RetroKeys("UID"))
+	system.PUID, err = s.readID("PUID", "UID")
 	if err != nil {
 		return system, err
 	}

-	system.PGID, err = s.env.Uint32Ptr("PGID", env.RetroKeys("GID"))
+	system.PGID, err = s.readID("PGID", "GID")
 	if err != nil {
 		return system, err
 	}

-	system.Timezone = s.env.String("TZ")
+	system.Timezone = getCleanedEnv("TZ")

 	return system, nil
 }
+
+var ErrSystemIDNotValid = errors.New("system ID is not valid")
+
+func (s *Source) readID(key, retroKey string) (
+	id *uint32, err error) {
+	idEnvKey, idString := s.getEnvWithRetro(key, retroKey)
+	if idString == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	const base = 10
+	const bitSize = 64
+	const max = uint64(^uint32(0))
+	idUint64, err := strconv.ParseUint(idString, base, bitSize)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable %s: %w: %s",
+			idEnvKey, ErrSystemIDNotValid, err)
+	} else if idUint64 > max {
+		return nil, fmt.Errorf("environment variable %s: %w: %d: must be between 0 and %d",
+			idEnvKey, ErrSystemIDNotValid, idUint64, max)
+	}
+
+	return uint32Ptr(uint32(idUint64)), nil
+}
--- a/internal/configuration/sources/env/system_test.go
+++ b/internal/configuration/sources/env/system_test.go
@@ -0,0 +1,88 @@
+package env
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Reader_readID(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		keyPrefix      string
+		keyValue       string
+		retroKeyPrefix string
+		retroValue     string
+		id             *uint32
+		errWrapped     error
+		errMessage     string
+	}{
+		"empty string": {
+			keyPrefix:      "ID",
+			retroKeyPrefix: "RETRO_ID",
+		},
+		"invalid string": {
+			keyPrefix:      "ID",
+			keyValue:       "invalid",
+			retroKeyPrefix: "RETRO_ID",
+			errWrapped:     ErrSystemIDNotValid,
+			errMessage: `environment variable IDTest_Reader_readID/invalid_string: ` +
+				`system ID is not valid: ` +
+				`strconv.ParseUint: parsing "invalid": invalid syntax`,
+		},
+		"negative number": {
+			keyPrefix:      "ID",
+			keyValue:       "-1",
+			retroKeyPrefix: "RETRO_ID",
+			errWrapped:     ErrSystemIDNotValid,
+			errMessage: `environment variable IDTest_Reader_readID/negative_number: ` +
+				`system ID is not valid: ` +
+				`strconv.ParseUint: parsing "-1": invalid syntax`,
+		},
+		"id 1000": {
+			keyPrefix:      "ID",
+			keyValue:       "1000",
+			retroKeyPrefix: "RETRO_ID",
+			id:             uint32Ptr(1000),
+		},
+		"max id": {
+			keyPrefix:      "ID",
+			keyValue:       "4294967295",
+			retroKeyPrefix: "RETRO_ID",
+			id:             uint32Ptr(4294967295),
+		},
+		"above max id": {
+			keyPrefix:      "ID",
+			keyValue:       "4294967296",
+			retroKeyPrefix: "RETRO_ID",
+			errWrapped:     ErrSystemIDNotValid,
+			errMessage: `environment variable IDTest_Reader_readID/above_max_id: ` +
+				`system ID is not valid: 4294967296: must be between 0 and 4294967295`,
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			suffix := t.Name()
+			key := testCase.keyPrefix + suffix
+			retroKey := testCase.retroKeyPrefix + suffix
+
+			setTestEnv(t, key, testCase.keyValue)
+			setTestEnv(t, retroKey, testCase.retroValue)
+
+			source := &Source{}
+			id, err := source.readID(key, retroKey)
+
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if err != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+
+			assert.Equal(t, testCase.id, id)
+		})
+	}
+}
--- a/internal/configuration/sources/env/unbound.go
+++ b/internal/configuration/sources/env/unbound.go
@@ -1,35 +1,37 @@
 package env

 import (
+	"fmt"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

-func (s *Source) readUnbound() (unbound settings.Unbound, err error) {
-	unbound.Providers = s.env.CSV("DOT_PROVIDERS")
+func readUnbound() (unbound settings.Unbound, err error) {
+	unbound.Providers = envToCSV("DOT_PROVIDERS")

-	unbound.Caching, err = s.env.BoolPtr("DOT_CACHING")
+	unbound.Caching, err = envToBoolPtr("DOT_CACHING")
 	if err != nil {
-		return unbound, err
+		return unbound, fmt.Errorf("environment variable DOT_CACHING: %w", err)
 	}

-	unbound.IPv6, err = s.env.BoolPtr("DOT_IPV6")
+	unbound.IPv6, err = envToBoolPtr("DOT_IPV6")
 	if err != nil {
-		return unbound, err
+		return unbound, fmt.Errorf("environment variable DOT_IPV6: %w", err)
 	}

-	unbound.VerbosityLevel, err = s.env.Uint8Ptr("DOT_VERBOSITY")
+	unbound.VerbosityLevel, err = envToUint8Ptr("DOT_VERBOSITY")
 	if err != nil {
-		return unbound, err
+		return unbound, fmt.Errorf("environment variable DOT_VERBOSITY: %w", err)
 	}

-	unbound.VerbosityDetailsLevel, err = s.env.Uint8Ptr("DOT_VERBOSITY_DETAILS")
+	unbound.VerbosityDetailsLevel, err = envToUint8Ptr("DOT_VERBOSITY_DETAILS")
 	if err != nil {
-		return unbound, err
+		return unbound, fmt.Errorf("environment variable DOT_VERBOSITY_DETAILS: %w", err)
 	}

-	unbound.ValidationLogLevel, err = s.env.Uint8Ptr("DOT_VALIDATION_LOGLEVEL")
+	unbound.ValidationLogLevel, err = envToUint8Ptr("DOT_VALIDATION_LOGLEVEL")
 	if err != nil {
-		return unbound, err
+		return unbound, fmt.Errorf("environment variable DOT_VALIDATION_LOGLEVEL: %w", err)
 	}

 	return unbound, nil
--- a/internal/configuration/sources/env/updater.go
+++ b/internal/configuration/sources/env/updater.go
@@ -1,11 +1,14 @@
 package env

 import (
+	"fmt"
+	"time"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

-func (s *Source) readUpdater() (updater settings.Updater, err error) {
-	updater.Period, err = s.env.DurationPtr("UPDATER_PERIOD")
+func readUpdater() (updater settings.Updater, err error) {
+	updater.Period, err = readUpdaterPeriod()
 	if err != nil {
 		return updater, err
 	}
@@ -15,16 +18,29 @@ func (s *Source) readUpdater() (updater settings.Updater, err error) {
 		return updater, err
 	}

-	updater.MinRatio, err = s.env.Float64("UPDATER_MIN_RATIO")
+	updater.MinRatio, err = envToFloat64("UPDATER_MIN_RATIO")
 	if err != nil {
-		return updater, err
+		return updater, fmt.Errorf("environment variable UPDATER_MIN_RATIO: %w", err)
 	}

-	updater.Providers = s.env.CSV("UPDATER_VPN_SERVICE_PROVIDERS")
+	updater.Providers = envToCSV("UPDATER_VPN_SERVICE_PROVIDERS")

 	return updater, nil
 }

+func readUpdaterPeriod() (period *time.Duration, err error) {
+	s := getCleanedEnv("UPDATER_PERIOD")
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+	period = new(time.Duration)
+	*period, err = time.ParseDuration(s)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable UPDATER_PERIOD: %w", err)
+	}
+	return period, nil
+}
+
 func readUpdaterDNSAddress() (address string, err error) {
 	// TODO this is currently using Cloudflare in
 	// plaintext to not be blocked by DNS over TLS by default.
--- a/internal/configuration/sources/env/version.go
+++ b/internal/configuration/sources/env/version.go
@@ -1,14 +1,32 @@
 package env

 import (
+	"fmt"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/govalid/binary"
 )

-func (s *Source) readVersion() (version settings.Version, err error) {
-	version.Enabled, err = s.env.BoolPtr("VERSION_INFORMATION")
+func readVersion() (version settings.Version, err error) {
+	version.Enabled, err = readVersionEnabled()
 	if err != nil {
 		return version, err
 	}

 	return version, nil
 }
+
+func readVersionEnabled() (enabled *bool, err error) {
+	s := getCleanedEnv("VERSION_INFORMATION")
+	if s == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	enabled = new(bool)
+	*enabled, err = binary.Validate(s)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable VERSION_INFORMATION: %w", err)
+	}
+
+	return enabled, nil
+}
--- a/internal/configuration/sources/env/vpn.go
+++ b/internal/configuration/sources/env/vpn.go
@@ -2,12 +2,13 @@ package env

 import (
 	"fmt"
+	"strings"

 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

 func (s *Source) readVPN() (vpn settings.VPN, err error) {
-	vpn.Type = s.env.String("VPN_TYPE")
+	vpn.Type = strings.ToLower(getCleanedEnv("VPN_TYPE"))

 	vpn.Provider, err = s.readProvider(vpn.Type)
 	if err != nil {
--- a/internal/configuration/sources/env/wireguard.go
+++ b/internal/configuration/sources/env/wireguard.go
@@ -1,29 +1,44 @@
 package env

 import (
+	"fmt"
+	"net/netip"
+	"os"
+	"strings"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

 func (s *Source) readWireguard() (wireguard settings.Wireguard, err error) {
 	defer func() {
 		err = unsetEnvKeys([]string{"WIREGUARD_PRIVATE_KEY", "WIREGUARD_PRESHARED_KEY"}, err)
 	}()
-	wireguard.PrivateKey = s.env.Get("WIREGUARD_PRIVATE_KEY", env.ForceLowercase(false))
-	wireguard.PreSharedKey = s.env.Get("WIREGUARD_PRESHARED_KEY", env.ForceLowercase(false))
-	wireguard.Interface = s.env.String("VPN_INTERFACE",
-		env.RetroKeys("WIREGUARD_INTERFACE"), env.ForceLowercase(false))
-	wireguard.Implementation = s.env.String("WIREGUARD_IMPLEMENTATION")
-	wireguard.Addresses, err = s.env.CSVNetipPrefixes("WIREGUARD_ADDRESSES",
-		env.RetroKeys("WIREGUARD_ADDRESS"))
+	wireguard.PrivateKey = envToStringPtr("WIREGUARD_PRIVATE_KEY")
+	wireguard.PreSharedKey = envToStringPtr("WIREGUARD_PRESHARED_KEY")
+	_, wireguard.Interface = s.getEnvWithRetro("VPN_INTERFACE", "WIREGUARD_INTERFACE")
+	wireguard.Implementation = os.Getenv("WIREGUARD_IMPLEMENTATION")
+	wireguard.Addresses, err = s.readWireguardAddresses()
 	if err != nil {
 		return wireguard, err // already wrapped
 	}
-	mtuPtr, err := s.env.Uint16Ptr("WIREGUARD_MTU")
-	if err != nil {
-		return wireguard, err
-	} else if mtuPtr != nil {
-		wireguard.MTU = *mtuPtr
-	}
 	return wireguard, nil
 }
+
+func (s *Source) readWireguardAddresses() (addresses []netip.Prefix, err error) {
+	key, addressesCSV := s.getEnvWithRetro("WIREGUARD_ADDRESSES", "WIREGUARD_ADDRESS")
+	if addressesCSV == "" {
+		return nil, nil
+	}
+
+	addressStrings := strings.Split(addressesCSV, ",")
+	addresses = make([]netip.Prefix, len(addressStrings))
+	for i, addressString := range addressStrings {
+		addressString = strings.TrimSpace(addressString)
+		addresses[i], err = netip.ParsePrefix(addressString)
+		if err != nil {
+			return nil, fmt.Errorf("environment variable %s: %w", key, err)
+		}
+	}
+
+	return addresses, nil
+}
--- a/internal/configuration/sources/env/wireguardselection.go
+++ b/internal/configuration/sources/env/wireguardselection.go
@@ -1,23 +1,55 @@
 package env

 import (
+	"fmt"
+	"net/netip"
+
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
+	"github.com/qdm12/govalid/port"
 )

 func (s *Source) readWireguardSelection() (
 	selection settings.WireguardSelection, err error) {
-	selection.EndpointIP, err = s.env.NetipAddr("VPN_ENDPOINT_IP", env.RetroKeys("WIREGUARD_ENDPOINT_IP"))
+	selection.EndpointIP, err = s.readWireguardEndpointIP()
 	if err != nil {
 		return selection, err
 	}

-	selection.EndpointPort, err = s.env.Uint16Ptr("VPN_ENDPOINT_PORT", env.RetroKeys("WIREGUARD_ENDPOINT_PORT"))
+	selection.EndpointPort, err = s.readWireguardCustomPort()
 	if err != nil {
 		return selection, err
 	}

-	selection.PublicKey = s.env.String("WIREGUARD_PUBLIC_KEY", env.ForceLowercase(false))
+	selection.PublicKey = getCleanedEnv("WIREGUARD_PUBLIC_KEY")

 	return selection, nil
 }
+
+func (s *Source) readWireguardEndpointIP() (endpointIP netip.Addr, err error) {
+	key, value := s.getEnvWithRetro("VPN_ENDPOINT_IP", "WIREGUARD_ENDPOINT_IP")
+	if value == "" {
+		return endpointIP, nil
+	}
+
+	endpointIP, err = netip.ParseAddr(value)
+	if err != nil {
+		return endpointIP, fmt.Errorf("environment variable %s: %w", key, err)
+	}
+
+	return endpointIP, nil
+}
+
+func (s *Source) readWireguardCustomPort() (customPort *uint16, err error) {
+	key, value := s.getEnvWithRetro("VPN_ENDPOINT_PORT", "WIREGUARD_ENDPOINT_PORT")
+	if value == "" {
+		return nil, nil //nolint:nilnil
+	}
+
+	customPort = new(uint16)
+	*customPort, err = port.Validate(value)
+	if err != nil {
+		return nil, fmt.Errorf("environment variable %s: %w", key, err)
+	}
+
+	return customPort, nil
+}
--- a/internal/configuration/sources/secrets/helpers.go
+++ b/internal/configuration/sources/secrets/helpers.go
@@ -2,24 +2,35 @@ package secrets

 import (
 	"fmt"
+	"os"
+	"strings"

 	"github.com/qdm12/gluetun/internal/configuration/sources/files"
 	"github.com/qdm12/gluetun/internal/openvpn/extract"
-	"github.com/qdm12/gosettings/sources/env"
 )

-func (s *Source) readSecretFileAsStringPtr(secretPathEnvKey, defaultSecretPath string) (
+// getCleanedEnv returns an environment variable value with
+// surrounding spaces and trailing new line characters removed.
+func getCleanedEnv(envKey string) (value string) {
+	value = os.Getenv(envKey)
+	value = strings.TrimSpace(value)
+	value = strings.TrimSuffix(value, "\r\n")
+	value = strings.TrimSuffix(value, "\n")
+	return value
+}
+
+func readSecretFileAsStringPtr(secretPathEnvKey, defaultSecretPath string) (
 	stringPtr *string, err error) {
-	path := s.env.String(secretPathEnvKey, env.ForceLowercase(false))
+	path := getCleanedEnv(secretPathEnvKey)
 	if path == "" {
 		path = defaultSecretPath
 	}
 	return files.ReadFromFile(path)
 }

-func (s *Source) readPEMSecretFile(secretPathEnvKey, defaultSecretPath string) (
+func readPEMSecretFile(secretPathEnvKey, defaultSecretPath string) (
 	base64Ptr *string, err error) {
-	pemData, err := s.readSecretFileAsStringPtr(secretPathEnvKey, defaultSecretPath)
+	pemData, err := readSecretFileAsStringPtr(secretPathEnvKey, defaultSecretPath)
 	if err != nil {
 		return nil, fmt.Errorf("reading secret file: %w", err)
 	}
--- a/internal/configuration/sources/secrets/helpers_test.go
+++ b/internal/configuration/sources/secrets/helpers_test.go
@@ -1,92 +0,0 @@
-package secrets
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/qdm12/gosettings/sources/env"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func ptrTo[T any](value T) *T { return &value }
-
-func Test_readSecretFileAsStringPtr(t *testing.T) {
-	t.Parallel()
-
-	testCases := map[string]struct {
-		source                func(tempDir string) Source
-		secretPathEnvKey      string
-		defaultSecretFileName string
-		setupFile             func(tempDir string) error
-		stringPtr             *string
-		errWrapped            error
-		errMessage            string
-	}{
-		"no_secret_file": {
-			defaultSecretFileName: "default_secret_file",
-			secretPathEnvKey:      "SECRET_FILE",
-		},
-		"empty_secret_file": {
-			defaultSecretFileName: "default_secret_file",
-			secretPathEnvKey:      "SECRET_FILE",
-			setupFile: func(tempDir string) error {
-				secretFilepath := filepath.Join(tempDir, "default_secret_file")
-				return os.WriteFile(secretFilepath, nil, os.ModePerm)
-			},
-			stringPtr: ptrTo(""),
-		},
-		"default_secret_file": {
-			defaultSecretFileName: "default_secret_file",
-			secretPathEnvKey:      "SECRET_FILE",
-			setupFile: func(tempDir string) error {
-				secretFilepath := filepath.Join(tempDir, "default_secret_file")
-				return os.WriteFile(secretFilepath, []byte("A"), os.ModePerm)
-			},
-			stringPtr: ptrTo("A"),
-		},
-		"env_specified_secret_file": {
-			source: func(tempDir string) Source {
-				secretFilepath := filepath.Join(tempDir, "secret_file")
-				environ := []string{"SECRET_FILE=" + secretFilepath}
-				return Source{env: *env.New(environ, nil)}
-			},
-			defaultSecretFileName: "default_secret_file",
-			secretPathEnvKey:      "SECRET_FILE",
-			setupFile: func(tempDir string) error {
-				secretFilepath := filepath.Join(tempDir, "secret_file")
-				return os.WriteFile(secretFilepath, []byte("B"), os.ModePerm)
-			},
-			stringPtr: ptrTo("B"),
-		},
-	}
-
-	for name, testCase := range testCases {
-		testCase := testCase
-		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-			tempDir := t.TempDir()
-
-			var source Source
-			if testCase.source != nil {
-				source = testCase.source(tempDir)
-			}
-
-			defaultSecretPath := filepath.Join(tempDir, testCase.defaultSecretFileName)
-			if testCase.setupFile != nil {
-				err := testCase.setupFile(tempDir)
-				require.NoError(t, err)
-			}
-
-			stringPtr, err := source.readSecretFileAsStringPtr(
-				testCase.secretPathEnvKey, defaultSecretPath)
-
-			assert.Equal(t, testCase.stringPtr, stringPtr)
-			assert.ErrorIs(t, err, testCase.errWrapped)
-			if testCase.errWrapped != nil {
-				assert.EqualError(t, err, testCase.errMessage)
-			}
-		})
-	}
-}
--- a/internal/configuration/sources/secrets/httpproxy.go
+++ b/internal/configuration/sources/secrets/httpproxy.go
@@ -6,8 +6,8 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

-func (s *Source) readHTTPProxy() (settings settings.HTTPProxy, err error) {
-	settings.User, err = s.readSecretFileAsStringPtr(
+func readHTTPProxy() (settings settings.HTTPProxy, err error) {
+	settings.User, err = readSecretFileAsStringPtr(
 		"HTTPPROXY_USER_SECRETFILE",
 		"/run/secrets/httpproxy_user",
 	)
@@ -15,12 +15,12 @@ func (s *Source) readHTTPProxy() (settings settings.HTTPProxy, err error) {
 		return settings, fmt.Errorf("reading HTTP proxy user secret file: %w", err)
 	}

-	settings.Password, err = s.readSecretFileAsStringPtr(
+	settings.Password, err = readSecretFileAsStringPtr(
 		"HTTPPROXY_PASSWORD_SECRETFILE",
 		"/run/secrets/httpproxy_password",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading HTTP proxy password secret file: %w", err)
+		return settings, fmt.Errorf("reading OpenVPN password secret file: %w", err)
 	}

 	return settings, nil
--- a/internal/configuration/sources/secrets/openvpn.go
+++ b/internal/configuration/sources/secrets/openvpn.go
@@ -6,9 +6,9 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

-func (s *Source) readOpenVPN() (
+func readOpenVPN() (
 	settings settings.OpenVPN, err error) {
-	settings.User, err = s.readSecretFileAsStringPtr(
+	settings.User, err = readSecretFileAsStringPtr(
 		"OPENVPN_USER_SECRETFILE",
 		"/run/secrets/openvpn_user",
 	)
@@ -16,7 +16,7 @@ func (s *Source) readOpenVPN() (
 		return settings, fmt.Errorf("reading user file: %w", err)
 	}

-	settings.Password, err = s.readSecretFileAsStringPtr(
+	settings.Password, err = readSecretFileAsStringPtr(
 		"OPENVPN_PASSWORD_SECRETFILE",
 		"/run/secrets/openvpn_password",
 	)
@@ -24,7 +24,7 @@ func (s *Source) readOpenVPN() (
 		return settings, fmt.Errorf("reading password file: %w", err)
 	}

-	settings.Key, err = s.readPEMSecretFile(
+	settings.Key, err = readPEMSecretFile(
 		"OPENVPN_CLIENTKEY_SECRETFILE",
 		"/run/secrets/openvpn_clientkey",
 	)
@@ -32,7 +32,7 @@ func (s *Source) readOpenVPN() (
 		return settings, fmt.Errorf("reading client key file: %w", err)
 	}

-	settings.EncryptedKey, err = s.readPEMSecretFile(
+	settings.EncryptedKey, err = readPEMSecretFile(
 		"OPENVPN_ENCRYPTED_KEY_SECRETFILE",
 		"/run/secrets/openvpn_encrypted_key",
 	)
@@ -40,7 +40,7 @@ func (s *Source) readOpenVPN() (
 		return settings, fmt.Errorf("reading encrypted key file: %w", err)
 	}

-	settings.KeyPassphrase, err = s.readSecretFileAsStringPtr(
+	settings.KeyPassphrase, err = readSecretFileAsStringPtr(
 		"OPENVPN_KEY_PASSPHRASE_SECRETFILE",
 		"/run/secrets/openvpn_key_passphrase",
 	)
@@ -48,7 +48,7 @@ func (s *Source) readOpenVPN() (
 		return settings, fmt.Errorf("reading key passphrase file: %w", err)
 	}

-	settings.Cert, err = s.readPEMSecretFile(
+	settings.Cert, err = readPEMSecretFile(
 		"OPENVPN_CLIENTCRT_SECRETFILE",
 		"/run/secrets/openvpn_clientcrt",
 	)
--- a/internal/configuration/sources/secrets/reader.go
+++ b/internal/configuration/sources/secrets/reader.go
@@ -1,37 +1,29 @@
 package secrets

 import (
-	"os"
-
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gosettings/sources/env"
 )

-type Source struct {
-	env env.Env
-}
+type Source struct{}

 func New() *Source {
-	handleDeprecatedKey := (func(deprecatedKey, newKey string))(nil)
-	return &Source{
-		env: *env.New(os.Environ(), handleDeprecatedKey),
-	}
+	return &Source{}
 }

 func (s *Source) String() string { return "secret files" }

 func (s *Source) Read() (settings settings.Settings, err error) {
-	settings.VPN, err = s.readVPN()
+	settings.VPN, err = readVPN()
 	if err != nil {
 		return settings, err
 	}

-	settings.HTTPProxy, err = s.readHTTPProxy()
+	settings.HTTPProxy, err = readHTTPProxy()
 	if err != nil {
 		return settings, err
 	}

-	settings.Shadowsocks, err = s.readShadowsocks()
+	settings.Shadowsocks, err = readShadowsocks()
 	if err != nil {
 		return settings, err
 	}
--- a/internal/configuration/sources/secrets/shadowsocks.go
+++ b/internal/configuration/sources/secrets/shadowsocks.go
@@ -6,8 +6,8 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

-func (s *Source) readShadowsocks() (settings settings.Shadowsocks, err error) {
-	settings.Password, err = s.readSecretFileAsStringPtr(
+func readShadowsocks() (settings settings.Shadowsocks, err error) {
+	settings.Password, err = readSecretFileAsStringPtr(
 		"SHADOWSOCKS_PASSWORD_SECRETFILE",
 		"/run/secrets/shadowsocks_password",
 	)
--- a/internal/configuration/sources/secrets/vpn.go
+++ b/internal/configuration/sources/secrets/vpn.go
@@ -6,8 +6,8 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )

-func (s *Source) readVPN() (vpn settings.VPN, err error) {
-	vpn.OpenVPN, err = s.readOpenVPN()
+func readVPN() (vpn settings.VPN, err error) {
+	vpn.OpenVPN, err = readOpenVPN()
 	if err != nil {
 		return vpn, fmt.Errorf("reading OpenVPN settings: %w", err)
 	}
--- a/internal/constants/openvpn/versions.go
+++ b/internal/constants/openvpn/versions.go
@@ -1,6 +1,6 @@
 package openvpn

 const (
+	Openvpn24 = "2.4"
 	Openvpn25 = "2.5"
-	Openvpn26 = "2.6"
 )
--- a/internal/firewall/iptables.go
+++ b/internal/firewall/iptables.go
@@ -157,6 +157,13 @@ func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
 func (c *Config) acceptOutputFromIPToSubnet(ctx context.Context,
 	intf string, sourceIP netip.Addr, destinationSubnet netip.Prefix, remove bool) error {
 	doIPv4 := sourceIP.Is4() && destinationSubnet.Addr().Is4()
+	doIPv6 := sourceIP.Is6() && destinationSubnet.Addr().Is6()
+	if !doIPv4 && !doIPv6 {
+		c.logger.Debug(fmt.Sprintf(
+			"source IP address %s and destination subnet %s are not of the same IP family, skipping...",
+			sourceIP, destinationSubnet))
+		return nil
+	}

 	interfaceFlag := "-o " + intf
 	if intf == "*" { // all interfaces
--- a/internal/httpproxy/handler.go
+++ b/internal/httpproxy/handler.go
@@ -2,6 +2,7 @@ package httpproxy

 import (
 	"context"
+	"fmt"
 	"net/http"
 	"sync"
 	"time"
@@ -65,8 +66,5 @@ var hopHeaders = [...]string{ //nolint:gochecknoglobals

 // Do not follow redirect, but directly return the redirect response.
 func returnRedirect(*http.Request, []*http.Request) error {
-	// WARNING: do not wrap this error!
-	// The standard library code checking against it does not use
-	// Go 1.13 `errors.Is` but `==`, so we cannot wrap it.
-	return http.ErrUseLastResponse
+	return fmt.Errorf("%w", http.ErrUseLastResponse)
 }
--- a/internal/httpproxy/handler_test.go
+++ b/internal/httpproxy/handler_test.go
@@ -1,16 +0,0 @@
-package httpproxy
-
-import (
-	"net/http"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func Test_returnRedirect(t *testing.T) {
-	t.Parallel()
-
-	err := returnRedirect(nil, nil)
-
-	assert.Equal(t, http.ErrUseLastResponse, err)
-}
--- a/internal/httpserver/settings.go
+++ b/internal/httpserver/settings.go
@@ -7,7 +7,7 @@ import (
 	"os"
 	"time"

-	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
 	"github.com/qdm12/govalid/address"
 )
@@ -34,12 +34,12 @@ type Settings struct {
 }

 func (s *Settings) SetDefaults() {
-	s.Address = gosettings.DefaultString(s.Address, ":8000")
+	s.Address = helpers.DefaultString(s.Address, ":8000")
 	const defaultReadTimeout = 3 * time.Second
-	s.ReadHeaderTimeout = gosettings.DefaultNumber(s.ReadHeaderTimeout, defaultReadTimeout)
-	s.ReadTimeout = gosettings.DefaultNumber(s.ReadTimeout, defaultReadTimeout)
+	s.ReadHeaderTimeout = helpers.DefaultNumber(s.ReadHeaderTimeout, defaultReadTimeout)
+	s.ReadTimeout = helpers.DefaultNumber(s.ReadTimeout, defaultReadTimeout)
 	const defaultShutdownTimeout = 3 * time.Second
-	s.ShutdownTimeout = gosettings.DefaultNumber(s.ShutdownTimeout, defaultShutdownTimeout)
+	s.ShutdownTimeout = helpers.DefaultNumber(s.ShutdownTimeout, defaultShutdownTimeout)
 }

 func (s Settings) Copy() Settings {
@@ -54,25 +54,25 @@ func (s Settings) Copy() Settings {
 }

 func (s *Settings) MergeWith(other Settings) {
-	s.Address = gosettings.MergeWithString(s.Address, other.Address)
-	s.Handler = gosettings.MergeWithInterface(s.Handler, other.Handler)
+	s.Address = helpers.MergeWithString(s.Address, other.Address)
+	s.Handler = helpers.MergeWithHTTPHandler(s.Handler, other.Handler)
 	if s.Logger == nil {
 		s.Logger = other.Logger
 	}
-	s.ReadHeaderTimeout = gosettings.MergeWithNumber(s.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	s.ReadTimeout = gosettings.MergeWithNumber(s.ReadTimeout, other.ReadTimeout)
-	s.ShutdownTimeout = gosettings.MergeWithNumber(s.ShutdownTimeout, other.ShutdownTimeout)
+	s.ReadHeaderTimeout = helpers.MergeWithNumber(s.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	s.ReadTimeout = helpers.MergeWithNumber(s.ReadTimeout, other.ReadTimeout)
+	s.ShutdownTimeout = helpers.MergeWithNumber(s.ShutdownTimeout, other.ShutdownTimeout)
 }

 func (s *Settings) OverrideWith(other Settings) {
-	s.Address = gosettings.OverrideWithString(s.Address, other.Address)
-	s.Handler = gosettings.OverrideWithInterface(s.Handler, other.Handler)
+	s.Address = helpers.OverrideWithString(s.Address, other.Address)
+	s.Handler = helpers.OverrideWithHTTPHandler(s.Handler, other.Handler)
 	if other.Logger != nil {
 		s.Logger = other.Logger
 	}
-	s.ReadHeaderTimeout = gosettings.OverrideWithNumber(s.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	s.ReadTimeout = gosettings.OverrideWithNumber(s.ReadTimeout, other.ReadTimeout)
-	s.ShutdownTimeout = gosettings.OverrideWithNumber(s.ShutdownTimeout, other.ShutdownTimeout)
+	s.ReadHeaderTimeout = helpers.OverrideWithNumber(s.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	s.ReadTimeout = helpers.OverrideWithNumber(s.ReadTimeout, other.ReadTimeout)
+	s.ShutdownTimeout = helpers.OverrideWithNumber(s.ShutdownTimeout, other.ShutdownTimeout)
 }

 var (
@@ -85,7 +85,7 @@ var (

 func (s Settings) Validate() (err error) {
 	uid := os.Getuid()
-	err = address.Validate(s.Address, address.OptionListening(uid))
+	_, err = address.Validate(s.Address, address.OptionListening(uid))
 	if err != nil {
 		return err
 	}
--- a/internal/models/servers.go
+++ b/internal/models/servers.go
@@ -11,7 +11,7 @@ import (
 	"github.com/qdm12/gluetun/internal/constants/providers"
 )

-type AllServers struct { //nolint:musttag
+type AllServers struct {
 	Version           uint16 // used for migration of the top level scheme
 	ProviderToServers map[string]Servers
 }
--- a/internal/netlink/address.go
+++ b/internal/netlink/address.go
@@ -1,32 +1,14 @@
-//go:build linux || darwin
-
 package netlink

-import (
-	"github.com/vishvananda/netlink"
-)
+import "github.com/vishvananda/netlink"
+
+type Addr = netlink.Addr

 func (n *NetLink) AddrList(link Link, family int) (
 	addresses []Addr, err error) {
-	netlinkLink := linkToNetlinkLink(&link)
-	netlinkAddresses, err := netlink.AddrList(netlinkLink, family)
-	if err != nil {
-		return nil, err
-	}
-
-	addresses = make([]Addr, len(netlinkAddresses))
-	for i := range netlinkAddresses {
-		addresses[i].Network = netIPNetToNetipPrefix(netlinkAddresses[i].IPNet)
-	}
-
-	return addresses, nil
+	return netlink.AddrList(link, family)
 }

-func (n *NetLink) AddrReplace(link Link, addr Addr) error {
-	netlinkLink := linkToNetlinkLink(&link)
-	netlinkAddress := netlink.Addr{
-		IPNet: netipPrefixToIPNet(addr.Network),
-	}
-
-	return netlink.AddrReplace(netlinkLink, &netlinkAddress)
+func (n *NetLink) AddrAdd(link Link, addr *Addr) error {
+	return netlink.AddrAdd(link, addr)
 }
--- a/internal/netlink/address_unspecified.go
+++ b/internal/netlink/address_unspecified.go
@@ -1,12 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) AddrList(link Link, family int) (
-	addresses []Addr, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) AddrReplace(Link, Addr) error {
-	panic("not implemented")
-}
--- a/internal/netlink/conversion.go
+++ b/internal/netlink/conversion.go
@@ -1,62 +0,0 @@
-package netlink
-
-import (
-	"fmt"
-	"net"
-	"net/netip"
-)
-
-func netipPrefixToIPNet(prefix netip.Prefix) (ipNet *net.IPNet) {
-	if !prefix.IsValid() {
-		return nil
-	}
-
-	prefixAddr := prefix.Addr().Unmap()
-	ipMask := net.CIDRMask(prefix.Bits(), prefixAddr.BitLen())
-	ip := netipAddrToNetIP(prefixAddr)
-
-	return &net.IPNet{
-		IP:   ip,
-		Mask: ipMask,
-	}
-}
-
-func netIPNetToNetipPrefix(ipNet *net.IPNet) (prefix netip.Prefix) {
-	if ipNet == nil || (len(ipNet.IP) != net.IPv4len && len(ipNet.IP) != net.IPv6len) {
-		return prefix
-	}
-
-	var ip netip.Addr
-	if ipv4 := ipNet.IP.To4(); ipv4 != nil {
-		ip = netip.AddrFrom4([4]byte(ipv4))
-	} else {
-		ip = netip.AddrFrom16([16]byte(ipNet.IP))
-	}
-	bits, _ := ipNet.Mask.Size()
-	return netip.PrefixFrom(ip, bits)
-}
-
-func netipAddrToNetIP(address netip.Addr) (ip net.IP) {
-	switch {
-	case !address.IsValid():
-		return nil
-	case address.Is4() || address.Is4In6():
-		bytes := address.As4()
-		return net.IP(bytes[:])
-	default:
-		bytes := address.As16()
-		return net.IP(bytes[:])
-	}
-}
-
-func netIPToNetipAddress(ip net.IP) (address netip.Addr) {
-	if len(ip) != net.IPv4len && len(ip) != net.IPv6len {
-		return address // invalid
-	}
-
-	address, ok := netip.AddrFromSlice(ip)
-	if !ok {
-		panic(fmt.Sprintf("converting %#v to netip.Addr failed", ip))
-	}
-	return address.Unmap()
-}
--- a/internal/netlink/conversion_test.go
+++ b/internal/netlink/conversion_test.go
@@ -1,146 +0,0 @@
-package netlink
-
-import (
-	"net"
-	"net/netip"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func Test_netipPrefixToIPNet(t *testing.T) {
-	t.Parallel()
-
-	testCases := map[string]struct {
-		prefix netip.Prefix
-		ipNet  *net.IPNet
-	}{
-		"empty_prefix": {},
-		"IPv4_prefix": {
-			prefix: netip.PrefixFrom(netip.AddrFrom4([4]byte{1, 2, 3, 4}), 24),
-			ipNet: &net.IPNet{
-				IP:   net.IP{1, 2, 3, 4},
-				Mask: net.IPv4Mask(255, 255, 255, 0),
-			},
-		},
-		"IPv4-in-IPv6_prefix": {
-			prefix: netip.PrefixFrom(netip.AddrFrom16(
-				[16]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 1, 2, 3, 4}),
-				24),
-			ipNet: &net.IPNet{
-				IP:   net.IP{1, 2, 3, 4},
-				Mask: net.IPv4Mask(255, 255, 255, 0),
-			},
-		},
-		"IPv6_prefix": {
-			prefix: netip.PrefixFrom(netip.IPv6Loopback(), 8),
-			ipNet: &net.IPNet{
-				IP:   net.IPv6loopback,
-				Mask: net.IPMask{0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
-			},
-		},
-	}
-
-	for name, testCase := range testCases {
-		testCase := testCase
-		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-
-			ipNet := netipPrefixToIPNet(testCase.prefix)
-
-			assert.Equal(t, testCase.ipNet, ipNet)
-		})
-	}
-}
-
-func Test_netIPNetToNetipPrefix(t *testing.T) {
-	t.Parallel()
-
-	testCases := map[string]struct {
-		ipNet  *net.IPNet
-		prefix netip.Prefix
-	}{
-		"empty ipnet": {},
-		"custom sized IP in ipnet": {
-			ipNet: &net.IPNet{
-				IP: net.IP{1},
-			},
-		},
-		"IPv4 ipnet": {
-			ipNet: &net.IPNet{
-				IP:   net.IP{1, 2, 3, 4},
-				Mask: net.IPMask{255, 255, 255, 0},
-			},
-			prefix: netip.PrefixFrom(netip.AddrFrom4([4]byte{1, 2, 3, 4}), 24),
-		},
-		"IPv4-in-IPv6 ipnet": {
-			ipNet: &net.IPNet{
-				IP:   net.IPv4(1, 2, 3, 4),
-				Mask: net.IPMask{255, 255, 255, 0},
-			},
-			prefix: netip.PrefixFrom(netip.AddrFrom4([4]byte{1, 2, 3, 4}), 24),
-		},
-		"IPv6 ipnet": {
-			ipNet: &net.IPNet{
-				IP:   net.IPv6loopback,
-				Mask: net.IPMask{0xff},
-			},
-			prefix: netip.PrefixFrom(netip.IPv6Loopback(), 8),
-		},
-	}
-
-	for name, testCase := range testCases {
-		testCase := testCase
-		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-
-			prefix := netIPNetToNetipPrefix(testCase.ipNet)
-
-			assert.Equal(t, testCase.prefix, prefix)
-		})
-	}
-}
-
-func Test_netIPToNetipAddress(t *testing.T) {
-	t.Parallel()
-
-	testCases := map[string]struct {
-		ip           net.IP
-		address      netip.Addr
-		panicMessage string
-	}{
-		"nil_ip": {},
-		"ip_not_ipv4_or_ipv6": {
-			ip: net.IP{1},
-		},
-		"IPv4": {
-			ip:      net.IPv4(1, 2, 3, 4),
-			address: netip.AddrFrom4([4]byte{1, 2, 3, 4}),
-		},
-		"IPv6": {
-			ip:      net.IPv6zero,
-			address: netip.AddrFrom16([16]byte{}),
-		},
-		"IPv4 prefixed with 0xffff": {
-			ip:      net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 1, 2, 3, 4},
-			address: netip.AddrFrom4([4]byte{1, 2, 3, 4}),
-		},
-	}
-
-	for name, testCase := range testCases {
-		testCase := testCase
-		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-
-			if testCase.panicMessage != "" {
-				assert.PanicsWithValue(t, testCase.panicMessage, func() {
-					netIPToNetipAddress(testCase.ip)
-				})
-				return
-			}
-
-			address := netIPToNetipAddress(testCase.ip)
-			assert.Equal(t, testCase.address, address)
-		})
-	}
-}
--- a/internal/netlink/family.go
+++ b/internal/netlink/family.go
@@ -2,23 +2,39 @@ package netlink

 import (
 	"fmt"
+
+	"github.com/vishvananda/netlink"
 )

+//nolint:revive
 const (
-	FamilyAll = 0
-	FamilyV4  = 2
-	FamilyV6  = 10
+	FAMILY_ALL = netlink.FAMILY_ALL
+	FAMILY_V4  = netlink.FAMILY_V4
+	FAMILY_V6  = netlink.FAMILY_V6
 )

 func FamilyToString(family int) string {
 	switch family {
-	case FamilyAll:
-		return "all" //nolint:goconst
-	case FamilyV4:
+	case FAMILY_ALL:
+		return "all"
+	case FAMILY_V4:
 		return "v4"
-	case FamilyV6:
+	case FAMILY_V6:
 		return "v6"
 	default:
 		return fmt.Sprint(family)
 	}
 }
+
+func (n *NetLink) IsWireguardSupported() (ok bool, err error) {
+	families, err := netlink.GenlFamilyList()
+	if err != nil {
+		return false, fmt.Errorf("listing gen 1 families: %w", err)
+	}
+	for _, family := range families {
+		if family.Name == "wireguard" {
+			return true, nil
+		}
+	}
+	return false, nil
+}
--- a/internal/netlink/wireguard_test.go
+++ b/internal/netlink/wireguard_test.go
@@ -1,5 +1,3 @@
-//go:build linux || darwin
-
 package netlink

 import (
--- a/internal/netlink/ipv6.go
+++ b/internal/netlink/ipv6.go
@@ -2,31 +2,39 @@ package netlink

 import (
 	"fmt"
+
+	"github.com/vishvananda/netlink"
 )

 func (n *NetLink) IsIPv6Supported() (supported bool, err error) {
-	routes, err := n.RouteList(FamilyV6)
+	links, err := n.LinkList()
 	if err != nil {
-		return false, fmt.Errorf("listing IPv6 routes: %w", err)
+		return false, fmt.Errorf("listing links: %w", err)
 	}

-	// Check each route for IPv6 due to Podman bug listing IPv4 routes
-	// as IPv6 routes at container start, see:
-	// https://github.com/qdm12/gluetun/issues/1241#issuecomment-1333405949
-	for _, route := range routes {
-		sourceIsIPv6 := route.Src.IsValid() && route.Src.Is6()
-		destinationIsIPv6 := route.Dst.IsValid() && route.Dst.Addr().Is6()
-		if sourceIsIPv6 || destinationIsIPv6 {
-			link, err := n.LinkByIndex(route.LinkIndex)
-			if err != nil {
-				return false, fmt.Errorf("finding IPv6 supported link: %w", err)
+	var totalRoutes uint
+	for _, link := range links {
+		routes, err := n.RouteList(link, netlink.FAMILY_V6)
+		if err != nil {
+			return false, fmt.Errorf("listing IPv6 routes for link %s: %w",
+				link.Attrs().Name, err)
+		}
+
+		// Check each route for IPv6 due to Podman bug listing IPv4 routes
+		// as IPv6 routes at container start, see:
+		// https://github.com/qdm12/gluetun/issues/1241#issuecomment-1333405949
+		for _, route := range routes {
+			sourceIsIPv6 := route.Src != nil && route.Src.To4() == nil
+			destinationIsIPv6 := route.Dst != nil && route.Dst.IP.To4() == nil
+			if sourceIsIPv6 || destinationIsIPv6 {
+				n.debugLogger.Debugf("IPv6 is supported by link %s", link.Attrs().Name)
+				return true, nil
 			}
-			n.debugLogger.Debugf("IPv6 is supported by link %s", link.Name)
-			return true, nil
+			totalRoutes++
 		}
 	}

-	n.debugLogger.Debugf("IPv6 is not supported after searching %d routes",
-		len(routes))
+	n.debugLogger.Debugf("IPv6 is not supported after searching %d links and %d routes",
+		len(links), totalRoutes)
 	return false, nil
 }
--- a/internal/netlink/link.go
+++ b/internal/netlink/link.go
@@ -1,105 +1,37 @@
-//go:build linux || darwin
-
 package netlink

 import "github.com/vishvananda/netlink"

+type (
+	Link      = netlink.Link
+	Bridge    = netlink.Bridge
+	Wireguard = netlink.Wireguard
+)
+
 func (n *NetLink) LinkList() (links []Link, err error) {
-	netlinkLinks, err := netlink.LinkList()
-	if err != nil {
-		return nil, err
-	}
-
-	links = make([]Link, len(netlinkLinks))
-	for i := range netlinkLinks {
-		links[i] = netlinkLinkToLink(netlinkLinks[i])
-	}
-
-	return links, nil
+	return netlink.LinkList()
 }

 func (n *NetLink) LinkByName(name string) (link Link, err error) {
-	netlinkLink, err := netlink.LinkByName(name)
-	if err != nil {
-		return Link{}, err
-	}
-
-	return netlinkLinkToLink(netlinkLink), nil
+	return netlink.LinkByName(name)
 }

 func (n *NetLink) LinkByIndex(index int) (link Link, err error) {
-	netlinkLink, err := netlink.LinkByIndex(index)
-	if err != nil {
-		return Link{}, err
-	}
-
-	return netlinkLinkToLink(netlinkLink), nil
+	return netlink.LinkByIndex(index)
 }

-func (n *NetLink) LinkAdd(link Link) (linkIndex int, err error) {
-	netlinkLink := linkToNetlinkLink(&link)
-	err = netlink.LinkAdd(netlinkLink)
-	if err != nil {
-		return 0, err
-	}
-	return netlinkLink.Attrs().Index, nil
+func (n *NetLink) LinkAdd(link Link) (err error) {
+	return netlink.LinkAdd(link)
 }

 func (n *NetLink) LinkDel(link Link) (err error) {
-	return netlink.LinkDel(linkToNetlinkLink(&link))
+	return netlink.LinkDel(link)
 }

-func (n *NetLink) LinkSetUp(link Link) (linkIndex int, err error) {
-	netlinkLink := linkToNetlinkLink(&link)
-	err = netlink.LinkSetUp(netlinkLink)
-	if err != nil {
-		return 0, err
-	}
-	return netlinkLink.Attrs().Index, nil
+func (n *NetLink) LinkSetUp(link Link) (err error) {
+	return netlink.LinkSetUp(link)
 }

 func (n *NetLink) LinkSetDown(link Link) (err error) {
-	return netlink.LinkSetDown(linkToNetlinkLink(&link))
-}
-
-type netlinkLinkImpl struct {
-	attrs    *netlink.LinkAttrs
-	linkType string
-}
-
-func (n *netlinkLinkImpl) Attrs() *netlink.LinkAttrs {
-	return n.attrs
-}
-
-func (n *netlinkLinkImpl) Type() string {
-	return n.linkType
-}
-
-func netlinkLinkToLink(netlinkLink netlink.Link) Link {
-	attributes := netlinkLink.Attrs()
-	return Link{
-		Type:      netlinkLink.Type(),
-		Name:      attributes.Name,
-		Index:     attributes.Index,
-		EncapType: attributes.EncapType,
-		MTU:       uint16(attributes.MTU),
-	}
-}
-
-// Warning: we must return `netlink.Link` and not `netlinkLinkImpl`
-// so that the vishvananda/netlink package can compare the returned
-// value against an untyped nil.
-func linkToNetlinkLink(link *Link) netlink.Link {
-	if link == nil {
-		return nil
-	}
-	return &netlinkLinkImpl{
-		linkType: link.Type,
-		attrs: &netlink.LinkAttrs{
-			Name:      link.Name,
-			Index:     link.Index,
-			EncapType: link.EncapType,
-			MTU:       int(link.MTU),
-		},
-	}
+	return netlink.LinkSetDown(link)
 }
--- a/internal/netlink/link_unspecified.go
+++ b/internal/netlink/link_unspecified.go
@@ -1,31 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) LinkList() (links []Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkByName(name string) (link Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkByIndex(index int) (link Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkAdd(link Link) (linkIndex int, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkDel(link Link) (err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkSetUp(link Link) (linkIndex int, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkSetDown(link Link) (err error) {
-	panic("not implemented")
-}
--- a/internal/netlink/linkattrs.go
+++ b/internal/netlink/linkattrs.go
@@ -0,0 +1,9 @@
+package netlink
+
+import "github.com/vishvananda/netlink"
+
+type LinkAttrs = netlink.LinkAttrs
+
+func NewLinkAttrs() LinkAttrs {
+	return netlink.NewLinkAttrs()
+}
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Quentin McGaw	6d48f9c2ba	fix(routing): net.IPNet to netip.Prefix conversion	2023-05-22 05:56:27 +00:00
Quentin McGaw	f712d77642	fix(firewall): prevent IP family mix in `acceptOutputFromIPToSubnet`	2023-05-21 18:06:18 +00:00