diff --git a/nixops/desktop.nix b/nixops/desktop.nix
index ae117b2..a7274a2 100644
--- a/nixops/desktop.nix
+++ b/nixops/desktop.nix
@@ -16,6 +16,7 @@ in
     ];
 
   networking.hostName = host;
+  networking.firewall.allowedTCPPorts = [ 1883 ];
 
   time.timeZone = "Asia/Hong_Kong";