Install sshguard by entering the following commands in the terminal:
sudo apt update sudo apt install sshguard
Description:
Protects from brute force attacks against ssh
Protects networked hosts from the today's widespread brute force attacks against ssh servers. It detects such attacks and blocks the author's address with a firewall rule.
Homepage: http://sshguard.sourceforge.net
Version: 1.7.1-1
Section: universe/net