VPS Guide: Your Go-To for VPS, Ubuntu & Command Line Success

Set Up Fail2ban Custom Filter on Ubuntu

Category: VPS Setup

Create a custom Fail2ban filter on Ubuntu for unique apps—install with

apt install fail2ban

then make a filter at /etc/fail2ban/filter d/custom conf with

nano /etc/fail2ban/filter.d/custom.conf

[Definition]\nfailregex = ^.*authentication failure.*client: .*$\nignoreregex =

Add a jail in /etc/fail2ban/jail d/custom conf:

[custom]\nenabled = true\nport = 12345\nlogpath = /var/log/custom.log\nmaxretry = 3\nbantime = 86400

Restart with

systemctl restart fail2ban

open port with

ufw allow 12345

On Linode test with fake logs—check bans with

fail2ban-client status custom

This secures niche services maintaining uptime with 24-hour bans