diff --git a/nixos/modules/services/networking/unifi.nix b/nixos/modules/services/networking/unifi.nix
index 89b9ac4eadf5..c82e0af2803d 100644
--- a/nixos/modules/services/networking/unifi.nix
+++ b/nixos/modules/services/networking/unifi.nix
@@ -121,11 +121,12 @@ in
     };
 
     networking.firewall = mkIf cfg.openPorts {
-      # https://help.ubnt.com/hc/en-us/articles/204910084-UniFi-Change-Default-Ports-for-Controller-and-UAPs
+      # https://help.ubnt.com/hc/en-us/articles/218506997
       allowedTCPPorts = [
         8080  # Port for UAP to inform controller.
         8880  # Port for HTTP portal redirect, if guest portal is enabled.
         8843  # Port for HTTPS portal redirect, ditto.
+        6789  # Port for UniFi mobile speed test.
       ];
       allowedUDPPorts = [
         3478  # UDP port used for STUN.