hardening

Signed-off-by: Hadi <112569860+anotherhadi@users.noreply.github.com>

server-modules/ssh.nix

@@ -10,6 +10,15 @@ in {
       PermitRootLogin = "no";
       PasswordAuthentication = false;
       AllowUsers = [username];
+      MaxAuthTries = 3;
+      LoginGraceTime = 20;
+      X11Forwarding = false;
+      AllowAgentForwarding = false;
+      AllowTcpForwarding = false;
+      ClientAliveInterval = 300;
+      ClientAliveCountMax = 2;
+      KexAlgorithms = ["curve25519-sha256" "curve25519-sha256@libssh.org"];
+      Ciphers = ["chacha20-poly1305@openssh.com" "aes256-gcm@openssh.com"];
     };
   };