Ethereal offers more protocol decoding and reassembly than any free sniffer out there and ranks well among the commercial tools. You've all used tools like tcpdump or windump to examine individual packets, but Ethereal makes it easier to make sense of a stream of ongoing network communications. Ethereal not only makes network troubleshooting work far easier, but also aids greatly in network forensics, the art of finding and examining an attack, by giving a better "big picture" view. Ethereal Packet Sniffing will show you how to make the most out of your use of Ethereal.
This excerpt is Jay Beale's introduction to Ethereal packet sniffing, part of his open source security book series. Here, he explains what Ethereal is and outlines the purpose behind his book.
Excerpted from Ethereal Packet Sniffing by Angela Orebaugh and Gilbert Ramirez (ISBN: 1-932266-82-8). Copyright 2004, Syngress Publishing, Inc. All rights reserved.