diff --git a/system/security/firewall.nix b/system/security/firewall.nix
index 60d339a..ff582da 100644
--- a/system/security/firewall.nix
+++ b/system/security/firewall.nix
@@ -4,8 +4,8 @@
   # Firewall
   networking.firewall.enable = true;
   # Open ports in the firewall.
-  # networking.firewall.allowedTCPPorts = [ ... ];
-  # networking.firewall.allowedUDPPorts = [ ... ];
+  networking.firewall.allowedTCPPorts = [ 22000 21027 ]; # syncthing
+  networking.firewall.allowedUDPPorts = [ 22000 21027 ]; # syncthing
   # Or disable the firewall altogether.
   # networking.firewall.enable = false;
 }