networking/module.nix: switch to Mullvad as DNS provider

modules/style/quickshell/module.nix

@@ -6,15 +6,24 @@
   ...
 }: let
   inherit (inputs) quickshell;
-in {
-  environment.systemPackages = with pkgs; [
-    quickshell.packages.x86_64-linux.default
-    qt6.qtimageformats
-    qt6.qt5compat
-    qt6.qtmultimedia
-    qt6.qtdeclarative
-  ];
 
-  # taken from outfoxxed.
-  qt.enable = true;
+  inherit (lib.modules) mkIf;
+  inherit (lib.options) mkEnableOption;
+
+  cfg = config.modules.theming.quickshell;
+in {
+  options.modules.theming.quickshell.enable = mkEnableOption "quickshell";
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = with pkgs; [
+      quickshell.packages.x86_64-linux.default
+      qt6.qtimageformats
+      qt6.qt5compat
+      qt6.qtmultimedia
+      qt6.qtdeclarative
+    ];
+
+    # taken from outfoxxed.
+    qt.enable = true;
+  };
 }

modules/system/os/networking/module.nix

@@ -18,17 +18,21 @@ in {
     };
 
     nameservers = [
-      # quad9 DNS
-      "9.9.9.9"
-      "2620::fe::fe"
+      # I have choosen Mullvad DNS as my standard DNS provider,
+      # as Quad9 at some point stopped resolving my universitie's IP address.
+      # Furthermore, Mullvad has a pretty good reputation when it comes to privacy
+      "194.242.2.4"
+      "2a07:e340::4"
     ];
   };
   services.resolved = {
     enable = true;
     dnssec = "false";
     dnsovertls = "opportunistic";
-    # quad9 dns
-    fallbackDns = ["9.9.9.9" "2620::fe::fe"];
+    fallbackDns = [
+      "194.242.2.4"
+      "2a07:e340::4"
+    ];
   };
   users.users.${username}.extraGroups = ["networkmanager"];