Find the port

[Jose Espinal]

HI gurus

  I am very new to networking so go easy on me, I am sure some of you in some point needed to find a port for an specific device, how do I go doing this when I have 4 switches and I don't know where is plugged in, but having the mac address for the device

I can go switch by switch and do an show mac address-table and that will help, but this is a small case of 4 switches how about if I had 45 switches, is there an easy way to find which port and on which switch the device is by connection to the first switch.

Thanks a bunch for your help and time

[Jon Marshall]

If CDP is running you simply follow the path.

So even if there are a lot of switches access switches they would usually all be connected to a pair of distribution switches.

What you do is a "sh mac address <mac address>" and it will probably show it being learnt on a trunk port.

You then do a "sh cdp neighbor <x/y> detail"  where <x/y> is the interface which gives you the IP of the next switch, you login to that switch and repeat the process.

It doesn't usually take very long to do.

Jon