debug to detect MAC in port of the Switch

Unanswered Question
Jul 2nd, 2008

Hello I need a debug that shows which MAC they are have beeb learning for the port of switch 3750 or I need to see in logging what MAC exists in each port of the switch.

Something como sh mac-a static but I require this be dynamic and sent a console o debug.

can you help me?

I have this problem too.
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Collin Clark Wed, 07/02/2008 - 07:48

You don't need a debug, you can use the following command(s)

show mac-address interface fastethernet0/1

If you know the IP address and want to find the MAC and which port it's plugged into-

show mac-address address [mac address]

Hope that helps

zztopping Wed, 07/02/2008 - 08:23

or show mac-address dynamic to show all learned MACs on all ports in a table

Giuseppe Larosa Wed, 07/02/2008 - 12:07

Hello Collin,

If you know the IP address and want to find the MAC

you do sh ip arp on default gateway for that address

then on switch

sh mac-address address

if you have multiple switches you start from the core switch(es), find out the interface where the mac address has been learned and with sh cdp n you find the access layer switch

then you go in telnet/ssh to the access-layer switch repeat the command sh mac-address address and you find the port where the device is connected to.

Of course, you have just forgotten to list the sh ip arp (mistyping) but it was in your thoughts

hope to help



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