pop3d brute force attack

[FeraTechInc]

How can I stop this attack?

Aug 11 11:22:59 server pop3d: Connection, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: Connection, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: LOGIN FAILED, user=login, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: Connection, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: LOGIN FAILED, user=louise, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: LOGIN FAILED, user=lloyd, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: LOGIN FAILED, user=logan, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: LOGOUT, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 server pop3d: Disconnected, ip=[::ffff:212.58.8.78]
Aug 11 11:22:59 fserver pop3d: Connection, ip=[::ffff:212.58.8.78]

[TechAvenue]

use fail2ban

[FeraTechInc]

Sorry, just figured it out.

Fail2ban is installed.

However, the "CourierAuth" section was set to disabled.

It is enabled, the jerk trying to hack me is banned.