Isoqlog is an MTA log analysis program written in C. It is designed to scan qmail, Postfix, Sendmail, and Exim logfiles and produce usage statistics in HTML for viewing through a browser. It produces a "top domains" statistic according to sender, receiver, total mails, and bytes, and keeps the main domain mail statistics with regard to day's top domain, and top users values for per day, per month, and per year.
Bruteblock allows system administrators to block various bruteforce attacks on UNIX services. The program analyzes system logs and adds attackers' IP addresses into the ipfw2 table, effectively blocking them. Addresses are automatically removed from the table after specified amount of time. Bruteblock uses regular expressions to parse logs, which gives it enough flexibility to be used with almost any network service. Bruteblock doesn't use any external programs and works with ipfw2 tables via the raw sockets API.