Mac address and port

Unanswered Question
Apr 24th, 2007

Hi all,

We have a 1721 box configured with a Vlan, two ports added to this Vlan. I wonder how to know what mac address is linked to fas1 and what mac address is linked to fas2. I have been trying lots of commands getting just informacion about the vlan but not about the ports.

thx in advance

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ankbhasi Tue, 04/24/2007 - 07:07

Hi Enriq,

I believe you have ether switch modules installed on 1721 box? If yes you can issue a command "sh int fa1/1 and sh int fa1/2"



enriquebs Tue, 04/24/2007 - 07:18

Hi Ankur,

Yes, I have a switch module, but what I wanna get are the mac addresses dynamically cached in each port. Until now all commands say that are learned via Vlan901 without give any further information about ports.


ankbhasi Tue, 04/24/2007 - 07:23

Hi Enriq,

So you will like to know the mac address learned dynamically on all ports like you get on any catalyst switches correct?

If yes you can issue a command "sh mac-address-table dynamic"

Also check this link if you are looking for some configuration guide and show commands available on ether switch module



*Pls rate all helpfull post

enriquebs Tue, 04/24/2007 - 07:26

Well, the Wic is a 4-port and the sh mac-add tab command is not supported in the 1721 box.


enriquebs Tue, 04/24/2007 - 12:18


I have tried that command, don't shows anything. sh ip arp shows mac addresses but don't give informacion about the port, just about the vlan.


enriquebs Wed, 04/25/2007 - 01:27

Hi all,

Finally I have the answer, sh controllers is the command. Here is the relevant output:

Mac Address | Ports | Entry State


00-00-00-00-00-00 | 0x20 | 0x0D

00-14-38-C9-7E-0A | 0x04 | 0x0E

00-16-46-D9-AE-0D | 0x20 | 0x0F

00-16-47-46-DC-14 | 0x20 | 0x0E

00-16-47-46-DC-15 | 0x20 | 0x0E

00-16-47-46-DC-16 | 0x20 | 0x0E

00-16-47-46-DC-17 | 0x20 | 0x0E

00-80-9F-5D-A8-5E | 0x01 | 0x0D

00-80-9F-5D-A8-80 | 0x02 | 0x0E

01-00-0C-CC-CC-CC | 0x20 | 0x0E

01-00-0C-CC-CC-CD | 0x20 | 0x0E

I can see the macs learned in ports 1, 2 and 4.


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