Install denyhosts by entering the following commands in the terminal:
sudo apt update sudo apt install denyhosts
Description:
Utility to help sys admins thwart SSH crackers
DenyHosts is a program that automatically blocks SSH brute-force attacks by adding entries to /etc/hosts.deny. It will also inform Linux administrators about offending hosts, attacked users and suspicious logins. . Synchronization with a central server is possible too. . Differently from other software that do same work, denyhosts doesn't need support for packet filtering or any other kind of firewall in your kernel. . DenyHosts unfortunately does not support IPv6.
Homepage: https://github.com/denyhosts/denyhosts
Version: 2.10-2
Section: universe/net