Configure single-client OpenVPN

nix/system/network.nix

@@ -0,0 +1,15 @@
+{ ... }: {
+  networking = {
+    hostName = "eve-psr-nix0";
+    firewall = {
+      allowedTCPPorts = [ 22 80 443 ];
+      allowedUDPPorts = [ 22 80 443 53 1194 ];
+      trustedInterfaces = [ "tun0" ];
+    };
+    nat = {
+      enable = true;
+      externalInterface = "enp1s0";
+      internalInterfaces = [ "tun0" ];
+    };
+  };
+}