server7: fix the bridge

hosts/server7/configuration.nix

@@ -104,6 +104,10 @@ in {
     };
   };
 
+  boot.kernel.sysctl."net.bridge.bridge-nf-call-arptables" = 0;
+  boot.kernel.sysctl."net.bridge.bridge-nf-call-iptables" = 0;
+  boot.kernel.sysctl."net.bridge.bridge-nf-call-ip6tables" = 0;
+
   environment.systemPackages = with pkgs; [ tmux htop vim gitMinimal nixfmt ];
 
   services.collectd.extraConfig = ''