These tools are made available with no warranty. Sans does not provide any statement, explicit or implied, of fitness or security in the use of these tools. Use at your own risk.
The Ethereal, Ngrep, Tcpdump, and Windump packages can be found in their corresponding directories. All of these depend on the Libpcap library (Unix) or Winpcap library for their operation - please install this first.
Sample packet capture files are also available, courtesy of the Ethereal project.