Brute-force attacks against SSH frequently target internet facing Linux systems, such as Debian, Ubuntu, Arch Linux, Linux Mint, Kali Linux, Raspberry Pi OS (Raspbian), Gentoo, etc. Fail2ban resolves this by monitoring authentication logs and dynamically updating firewall rules to block IP addresses that show malicious behavior such as repeated failed login attempts. This article covers configuring custom jail parameters and applying the rules to protect SSH. When does Fail2ban actually improve SSH security? The real value of Fail2ban depends on the authentication model. If a server allows password authentication, Fail2ban reduces exposure to automated brute-force attacks by limiting how many … Continue reading →