Fix #142

README.md

@@ -79,6 +79,16 @@
 
     - If you have a host or router firewall, please refer [to the firewall documentation](https://github.com/qdm12/private-internet-access-docker/blob/master/doc/firewall.md)
 
+1. On some devices such as Synology or Qnap machines, it's required to setup your tunnel device `/dev/net/tun` on your host:
+
+    ```sh
+    insmod /lib/modules/tun.ko
+    # or
+    modprobe tun
+    ```
+
+    You can verify it's here with `ls /dev/net`
+
 1. Launch the container with:
 
     ```bash