Firewall Blocks :
To complement the ConfigServer Firewall (csf), we have developed a Login Failure Daemon (LFD) process that runs all the time and periodically (every X seconds) scans the latest log file entries for login attempts against your server that continually fail within a short period of time. Such attempts are often called"Brute-force attacks" and the daemon process responds very quickly to such patterns and blocks offending IP's quickly. Other similar products run every x minutes via cron and as such often miss break-in attempts until after they've finished, our daemon eliminates such long waits and makes it much more effective at performing its task.
Login tracking is an extension of lfd, it keeps track of POP3 and IMAP logins and limits them to X connections per hour per account per IP address.