opinions on the suggested fail2ban and ufw?
replies(5):
It won't protect you from a direct attack, and it's no substitute for good system security, but it can quickly block attackers who "scan" your system to see what's running, to see what they can attack. It won't stop a determined attacker who will be able to attack from many locations, but that doesn't make it useless.
You can also use it actively to block people who do things like hammering a password form.