Fix NAT connectivity on Nebula

nixos/hosts/eidola/nebula.nix

@@ -7,6 +7,9 @@ in {
     group = userGroup;
   };
 
+  # TODO: why?
+  networking.firewall.allowedUDPPorts = [4242];
+
   gen.nebula = {
     enable = true;
     enableLighthouse = false;

nixos/modules/nebula/default.nix

@@ -56,7 +56,10 @@ with lib; let
     relays = lhsInternal;
     staticHostMap = lhs;
 
-    settings.punchy.punch = true;
+    settings.punchy = {
+      punch = true;
+      respond = true;
+    };
   };
 
   cfg = config.gen.nebula;