Comments on: How to Determine Which Switch and Port You are Connected To

By: Tony

Tony — Sat, 14 Feb 2009 13:01:55 +0000

Is there a method if you don't have access (telnet) to the switch? Like the Fluke LinkRunner device.

By: AWfki

AWfki — Wed, 01 Nov 2006 05:15:20 +0000

“show mac-address-table 0000.0000.0000″ is too much typing for me, especially as I’m frequently called on to find which interface a server or user is connected to. Because I’m lazy in an efficient kind of way I add the “shmac” alias to all my switches.

In config mode enter alias exec shmac SH MAC-address-table | include

Now when you want to find a server that’s got a mac address of 0102.0304.0506 you can just type shmac 0506
and nine times out of ten you’ll get the entry you’re looking for. You may get multiple entries if you’ve got two devices with MACs ending in 0506 so you could type the whole MAC address, but I did mention that I’m “efficient” so I rarely do.

I’d also like to note that while the author’s network may always use gig interface for switch connections it’s perfectly possible for a user to be connected to one so that’s not actually a guarantee that’s it’s an interswitch link. Figuring that out requires that you know your network; which means that I can’t think of a simple to explain way to figure out where the port shown leads to another switch.

By: aaronm

aaronm — Thu, 26 Jan 2006 08:26:40 +0000

If you can do all this on a network, they have some serious security concerns…. 8O

By: dat

dat — Tue, 06 Dec 2005 15:59:46 +0000

thank for this useful guide.

By: Caveman

Caveman — Thu, 05 May 2005 10:59:40 +0000

I have used this primarily on 2950 and 3550 switches running IOS. If you find any others this works on, or you find switches it does not work on, please let me know. Thanks.

It does not work on:
- 4000 series w/ CatOS