How to protect Horde Webmail (Plesk) against brute force attacks

This article outlines the process of configuring Fail2Ban to secure a Horde Webmail, running on a Plesk server, against brute force attacks.

Prerequisite: This article expects that you have already completed the installation of Fail2Ban as outlined here.

Once you have completed the installation of Fail2Ban –

1. Copy the Courier IMAP filter to a new filter for Horde:

# cp /etc/fail2ban/filter.d/courierlogin.conf /etc/fail2ban/filter.d/hordelogin.conf

2. Edit the contents of /etc/fail2ban/filter.d/hordelogin.conf

# nano -w /etc/fail2ban/filter.d/hordelogin.conf

The file should read:

[Definition]

failregex = FAILED LOGIN for *.* \[< HOST >\] .*$

ignoreregex =

3. Edit the Fail2Ban jail file:

# nano -w /etc/fail2ban/jail.conf

4. At the end of the file add: