diff --git a/configuration.nix b/configuration.nix
index 3a8d6c7..93aa36c 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -110,6 +110,9 @@
   # services.openssh.enable = true;
 
   # Open ports in the firewall.
+  networking.firewall = {
+    enable = true;
+  };
   # networking.firewall.allowedTCPPorts = [ ... ];
   # networking.firewall.allowedUDPPorts = [ ... ];
   # Or disable the firewall altogether.