pre-router: use internal nameserver

hosts/pre-router/dhcp.nix

@@ -28,7 +28,7 @@
             }
             {
               name = "domain-name-servers";
-              data = "10.42.10.1";
+              data = "10.42.10.8";
             }
             {
               name = "domain-name";

hosts/pre-router/router.nix

@@ -9,7 +9,7 @@
 
   networking.firewall.interfaces.ens19.allowedUDPPorts = [ 67 53 ];
   networking = {
-    nameservers = [ "141.24.40.3" "141.24.40.4" ];
+    nameservers = [ "10.42.10.8" "2a01:4f8:1c0c:8221::8" ];
     nat = {
       enable = true;
       extraCommands = "iptables -A INPUT -p icmp -j ACCEPT";