mini_nixcfg/imports/wireguard.nix

{ config, lib, pkgs, ... }:
{
  # Enable WireGuard
  networking.wireguard.enable = true;
  networking.wireguard.interfaces = {
    # "wg0" is the network interface name. You can name the interface arbitrarily.
    tr = {
      # Determines the IP address and subnet of the client's end of the tunnel interface.
      ips = [ "10.0.1.2/24" ];
      #listenPort = 51821; # to match firewall allowedUDPPorts (without this wg uses random port numbers)

      # Path to the private key file.
      #
      # Note: The private key can also be included inline via the privateKey option,
      # but this makes the private key world-readable; thus, using privateKeyFile is
      # recommended.
      privateKeyFile = "/root/wireguard-keys/private";

      peers = [
        # For a client configuration, one peer entry for the server will suffice.

        {
          # Public key of the server (not a file path).
          publicKey = "TSPq7sJbY9DNhCu76sc0s9wtFnfHhk/ud0D/JiEPfV4=";

          # Forward all the traffic via VPN.
          allowedIPs = [ "10.0.1.1" ];
          # Or forward only particular subnets
          #allowedIPs = [ "10.100.0.1" "91.108.12.0/22" ];

          # Set this to the server IP and port.
          endpoint = "79.72.30.126:51821"; # ToDo: route to endpoint not automatically configured https://wiki.archlinux.org/index.php/WireGuard#Loop_routing https://discourse.nixos.org/t/solved-minimal-firewall-setup-for-wireguard-client/7577

          # Send keepalives every 25 seconds. Important to keep NAT tables alive.
          persistentKeepalive = 25;
        }
      ];
    };
  };
}