diff --git a/nixos/modules/services/networking/websockify.nix b/nixos/modules/services/networking/websockify.nix
index c9219fc17d51..5e17e9bc7818 100644
--- a/nixos/modules/services/networking/websockify.nix
+++ b/nixos/modules/services/networking/websockify.nix
@@ -36,7 +36,7 @@ in
       portMap = mkOption {
         description = "Ports to map by default.";
         default = { };
-        type = types.attrsOf types.int;
+        type = types.attrsOf types.port;
       };
     };
   };