"Last month's article looked at iptables firewall management
with Big Fish. This month, let's will take a look at intrusion
detection using SNORT, along with its LAMP-based analysis add-on,
ACID, short for 'Analysis Console for Intrusion Databases.'
"SNORT, lovingly referred to as 'the pig,' is an advanced packet
sniffer and logger that analyzes traffic on your network. It can be
setup for protocol analysis, regular expression string matching,
and network attack detection, including buffer overflows, stealth
port scans, SMB probes, and many more..."