CDP Reporter

www.monkeymental.com is CDPR's home, but you can also find it at Sourceforge.
"cdpr is used to decode a Cisco Disovery Protocol (CDP) packet, by default it will report the device ID, the IP Address (of the device), and the port number that the machine is connected to. Optionally it will decode the entire CDP packet."
This is the most awesome utility made for troubleshooting VLAN issues. It's also great for determining if a port is working as you can just plug in, run cdpr and wait for the results - if you get a port number, the connection is live!
Versions 2.0 and up include a server-side script that allows you to log the hostname and physical location that are connected to a given switch port.
By running "cdpr -s -p /scripts/cdprs.php -n -l " - after installing the script in the appropriate location with the appropriate permissions (744 should work) - you'll find an entry added to the file "/tmp/cdprs.txt" on the server. With a little more Perl and Expect education on my part, I'll be able to use this log to add descriptions to my switch ports or locate a switch port by grep'ing the room number.
Oh, and by the way CDPR's author - Lance - is great! He's answered all my questions and even compiled a Windows version for me back in the 1.x versions.
- SLW