feat: refactor the modules/servers directory.

modules/servers/common/fail2ban.nix

@@ -0,0 +1,16 @@
+{...}: {
+  services.fail2ban = {
+    enable = true;
+    maxretry = 5;
+    ignoreIP = [
+      "65.21.241.194"
+    ];
+    bantime = "24h"; # Ban IPs for one day on the first ban
+    bantime-increment = {
+      enable = true; # Enable increment of bantime after each violation
+      multipliers = "1 2 4 8 16 32 64";
+      maxtime = "168h"; # Do not ban for more than 1 week
+      overalljails = true; # Calculate the bantime based on all the violations
+    };
+  };
+}