Packet Capture (Sniffer Traces)
Sometimes you may run into a problem, in which syslog, after running the debug commands, may not give very conclusive results because there may be other network-related issues that may affect the packet flow. Under this rare circumstance, capturing the sniffer traces simultaneously from incoming and outgoing interfaces segments may help in isolating the problem. A very popular and free downloadable sniffer software is Ethereal, www.ethereal.com