nixos/estuary: Implement recursive DNS

nixos/modules/common.nix

@@ -77,6 +77,11 @@ in
       boot = {
         # Use latest LTS release by default
         kernelPackages = mkDefault pkgs.linuxKernel.packages.linux_5_15;
+        kernel = {
+          sysctl = {
+            "net.ipv6.route.max_size" = mkDefault 16384;
+          };
+        };
         loader = {
           efi = {
             efiSysMountPoint = mkDefault "/boot";

nixos/modules/network.nix

@@ -12,7 +12,13 @@ in
         useNetworkd = mkDefault true;
       };
 
-      services.resolved.domains = [ config.networking.domain ];
+      services.resolved = {
+        domains = [ config.networking.domain ];
+        # Explicitly unset fallback DNS (Nix module will not allow for a blank config)
+        extraConfig = ''
+          FallbackDNS=
+        '';
+      };
     }
 
     (mkIf config.my.build.isDevVM {