Tracking down a switch port by MAC address

Hey all, I've been asked to track down a switch port by the MAC address of the connected device. It's a stack of 4 or 5 Cisco switches. I ran a show mac address-table and it returned a very long list. Is there any way to filter by the MAC address? If you need more info, I'll be able to access the stack tomorrow.

Thanks!

Find more posts tagged with

Save $250 on 2025 certification boot camps from Infosec!

Book now with code EOY2025

Button

Comments

thomas_

show mac-address table address hhh.hhh.hhh
show mac-address table | include [regex expression]

AvgITGeek

That did the trick! I was able to resolve my customers issue. Thanks much!

EDIT for more info. Customer called with a complaint that a certain computer kept getting assigned an address in a different VLAN. It has been a long time since my CCNA studies but I was able to get them a listing of the VLANS on this stack. Decided to track down the port via MAC. First time was unsuccessful because they were now wireless. I was able to track down where their WiFi MAC was being learned via show etherchannel summary and then a show cdp neighbor.

Once he plugged a non WiFi client into the network, I was able to find the port via show mac address-table address <MAC address> and when I did a show run interface gi2/0/23 it showed that port didn't have the VLAN access it needed. A quick config t interface gi2/0/23 and switchport access vlan 10 solved the issue.

Thanks again to thomas_ as that was the piece I was missing. I should start studying for the CCNA again. I so much want to finish my 2012 MCSA though. So many exams, so little time.