Set up Wireguard on OpenWrt
Wireguard offers a modern virtual private network (VPN) implementation, which was with version 5.6 incorporated into the Linux kernel. It can be easily set up on a OpenWrt router, server or client wise. The following covers the steps for setting it up as a server. OpenWrts Wiki contains this page, which has some hints, but isn't that elaborative about it.
After login in into OpenWrts administrator interface LuCI the packages
luci-app-wireguard need to be installed. The first one adds the possibility to configure Wireguard interfaces. For
luci-app-wireguard a language package needs to be installed as well, otherwise the
Wireguard page won't show up in the
Status menu. This page contains some status information about the current Wireguard "situation". In my case I've installed
luci-i18n-wireguard-en. Furthermore if you want that the QR Code is displayed on the
Wireguard page, install the package
qrencode as well. The installation of the mentioned packages can be done via the main menu
System and its entry
To be able to configure the Wireguard interface the network service needs to be restarted, after the packages are installed, so it picks up the newly installed protocol from
lucy-proto-wireguard. This can be done via the
Startup page in the
System menu. There you find the
network service, which should be restarted.
Now it's time to create a new network interface for the VPN. A new interface can be created with the button at the bottom on the
Network / Interfaces page. First a name for the interface should be picked.
wg0 does the job. For the protocol
Wireguard VPN is chosen.
In the next form, the private key, from which the peers public keys will be derived, can be generated by clicking the button under the field. The internal port we set to
1234 or something else, which is not used by router. Last but not least the IP network of this interface should be configured.
Change to the
Advanced Settings at the top. It's a good idea to define a fixed DNS server, so this doesn't need to be configured on the peers (clients). If there is no separate DNS server, it's sufficient to provide the routers IP address.
Firewall Settings, the question needs to be asked, with whom VPN clients are allowed to communicate? If the clients can communicate with other clients on the local area network select
LAN and if the vpn acts as a internet proxy
WAN can be selected. Maybe other configurations make sense here.
After saving and applying the new Wireguard interface, it's time to set up a port forwarding rule on the firewall. This page can be found under
Network and then
Firewall. As in most public networks not all ports are permitted, I usually choose
443 as this is usually open for HTTPS traffic. For even better result, Wireguard should be configured to use TCP instead of UDP.
This means the external port can be set to
443 and the internal to the port, where Wireguard is running on. The internal IP address also points to the device, where Wireguard is installed, which is in this case the router itself.
Finally it's time to add some peers. On the
Wireguard page which can be opened through the
Status menu, there should a QR Code be shown. The official Wireguard smartphone apps can scan this code.
After scanning this code you will be asked, how the tunnel should be named. Set a static internal IP address for this peer. If the Wireguard server is behind a NAT, what is very often the case, set the
Persistent Keepalive to
25. Set the
Endpoint to the WAN (public internet IP) of the router where the Wireguard server is installed.
With the public key and the other information this peer can now permitted to access the Wireguard server. In the previously created Wireguard interface (
Network menu and
Edit), a new peer should be created with the public key from the peer.
With this all the configuration is done and the testing with the first peer can begin.