fireparse is an ADMLogger plugin that emails a report of all packets that have been logged by the kernel's packet filtering subsystem (iptables/netfilter or ipchains). The report includes source and destination ports, direction, logged packet count, matched rule, and fully resolved host names (if available). The email report can be formatted to plain text or a colored HTML table.
Firewall Log Daemon is a program written in C which will watch for ipchains or iptables log alerts in realtime. The program will start a small daemon process that parses and resolves firewall logs by reading a FIFO that syslog writes to. It can queue a batch of alerts and mail them to you, or can be used in a script to crunch an existing log file or data stream. It features hostname, port, protocol, and ICMP type/code lookup, with output formatted by a user-defined template.
fwlogwatch is a packet filter and firewall log analyzer with support for Linux ipchains, Linux netfilter/iptables, Solaris/BSD/HP-UX/IRIX ipfilter, Cisco IOS, Cisco PIX/ASA, Netscreen, Elsa Lancom router, and Snort IDS log files. It can output its summaries in text and HTML and has a lot of options. fwlogwatch also features a realtime anomaly response capability with a Web interface.
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.