diff --git a/nixos/modules/services/networking/kresd.nix b/nixos/modules/services/networking/kresd.nix
index 0c7363e564dc..307414abf170 100644
--- a/nixos/modules/services/networking/kresd.nix
+++ b/nixos/modules/services/networking/kresd.nix
@@ -11,7 +11,7 @@ let
   mkListen = kind: addr: let
     al_v4 = builtins.match "([0-9.]+):([0-9]+)($)" addr;
     al_v6 = builtins.match "\\[(.+)]:([0-9]+)(%.*|$)" addr;
-    al_portOnly = builtins.match "([0-9]+)" addr;
+    al_portOnly = builtins.match "(^)([0-9]+)" addr;
     al = findFirst (a: a != null)
       (throw "services.kresd.*: incorrect address specification '${addr}'")
       [ al_v4 al_v6 al_portOnly ];