working bridge configuration

qemu-bridges.nix

@@ -4,9 +4,15 @@
         "enp4s0"
     ];
 
+    boot.kernel.sysctl."net.ipv4.ip_forward" = 1;
+
     networking.interfaces.virtbr0 = {
         useDHCP = true;
     };
 
-    virtualisation.libvirtd.allowedBridges = [ "virtbr0" ];
+    virtualisation.libvirtd = { 
+        enable = true;
+        allowedBridges = [ "virtbr0" ];
+        
+    };
 }