add fail2ban config

config/default.nix

@@ -1,4 +1,4 @@
-{...}: {
+{
   imports = [
     ./disks.nix
     ./hardware-configuration.nix
@@ -9,6 +9,7 @@
     ./nvim
     ./http
     ./search
+    ./security
   ];
   system.stateVersion = "25.05";
 }

config/security/default.nix

@@ -0,0 +1,3 @@
+{
+  imports = [./fail2ban.nix];
+}

config/security/fail2ban.nix

@@ -0,0 +1,14 @@
+{
+  services.fail2ban = {
+    enable = true;
+    maxretry = 5;
+    bantime = "6h";
+    bantime-increment = {
+      enable = true;
+      formula = "ban.Time * math.exp(float(ban.Count+1)*banFactor)/math.exp(1*banFactor)";
+      multipliers = "1 2 4 8 16 32 64";
+      rndtime = "6h";
+      overalljails = true;
+    };
+  };
+}