MAC address table entries

Unanswered Question
Nov 28th, 2008

When I do a 'show mac-address-table' entry on Cat 6500 I see duplicate entries for the given mac.

Could you please explain why is a Port-Channel Po1 also returned since the given mac is directly connected to the switch.

SWTICH#sh mac-address-table | i f3c0

* 11 0013.2222.f3c0 dynamic Yes 0 Gi4/3

* 10 0013.2222.f3c0 dynamic Yes 0 Po1


I have this problem too.
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Giuseppe Larosa Sat, 11/29/2008 - 02:50

Hello New,

if you have service modules in your C6500 this can happen.

For example on a chassis with CSM and FWSM. With the CSM used in bridged mode this is normal.

I suppose the two entries are in different vlans

If you like you can post

sh module

sh ethercha sum

to understand to what device Po1 connects

Hope to help


new_networker Sat, 11/29/2008 - 04:15

Po1 connects to the second chassis with exactly the same VLANs, other configurations etc.

The servers are dual-honed. However, the mac stated earlier I believe should only contain one entry.

Could you please elaborate on why this can happen in this scenario. Should this duplication be ignored. Thanks.


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