diff --git a/modules/services/matrix/default.nix b/modules/services/matrix/default.nix
index 9acd8c2..42c5cda 100644
--- a/modules/services/matrix/default.nix
+++ b/modules/services/matrix/default.nix
@@ -117,6 +117,15 @@ in
           };
         };
       }
+      # Dummy VHosts for port collision detection
+      {
+        subdomain = "matrix-federation";
+        port = federationPort.private;
+      }
+      {
+        subdomain = "matrix-client";
+        port = clientPort.private;
+      }
     ];
 
     # Those are too complicated to use my wrapper...