prepare configuration for server use

modules/default.nix

@@ -4,6 +4,7 @@
   ...
 }: let
   cfg = config.my;
+  helpers = import ../helpers;
 in {
   imports = [
     ./home
@@ -22,7 +23,7 @@ in {
     services.openssh = {
       enable = true;
       settings = {
-        PermitRootLogin = "no";
+        PermitRootLogin = helpers.mkIfElse config.my.server.enable "yes" "no";
         PasswordAuthentication = false;
         KbdInteractiveAuthentication = false;
       };

modules/desktop/default.nix

@@ -22,6 +22,8 @@ in {
 
       # Enable CUPS to print documents.
       printing.enable = true;
+
+      openssh.settings.PermitRootLogin = "no";
     };
 
     # Enable sound with pipewire.

modules/server/default.nix

@@ -0,0 +1,33 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}: let
+  cfg = config.my.server;
+in {
+  imports = [];
+
+  options.my.server = {
+    enable = lib.mkEnableOption "server role";
+  };
+
+  config = lib.mkIf cfg.enable {
+    services = {
+      services.openssh.enable = true;
+    };
+
+    programs = {
+    };
+
+    networking.firewall = {
+      allowedTCPPortRanges = [
+        {
+          # ssh
+          from = 22;
+          to = 22;
+        }
+      ];
+    };
+  };
+}