protect against brute force attacks on sshd and others
sshguard protects hosts from brute force attacks. It supports IPv6, whitelists and log authentication, interfaces with all the major firewalling systems, has a remarkably clever log analyzer, and is independent, fast and lightweight as it's written in C. Parsers cover OpenSSH, several MTAs, IMAP/POP3 and ftp daemons.
Homepage: https://www.sshguard.net/
Maintainer: Stuart Henderson <stu.ports@spacehopper.org>