fwmon is a firewall monitor for Linux. It integrates with ipchains/iptables to
give you realtime notification of firewall events. It has fairly customizable
output, allowing you to display a packet summary with hex and ASCII data dumps
to stdout, a logfile, tcpdump-style capture files, and even syslog. It also
boasts some simple security features such as the ability to chroot itself, and
operate in a non-root environment.
