Ghost MAC addresses

[joseph.williams@atos.net]

This will sound stupid and I'm probably missing something obvious. I'm mapping a very old segment for my company for moving the segment to a new location.

Using a combination of MAC-add tables and arp tables, I have found all the connections...except two.

They have mac addresses very similar to each other and I believe they are for old equipment that hasn't been there for two years or more. When I search the configs of the devices, one f them has the ip for that device.

Shouldn't that ip and mac have disappeared by now? I tried pinging the IP and it doesn't respond (but then again, it could have been an old ASA.

I'm baffled. Any ideas? Thanks Joe W

[Seb Rupik]

Hi there,

Out of interest what are the first six characters of the MAC address?

The entries in a MAC address table, assuming they are dynamic, while have a set lifetime and will be purged. Can you not trace the device down to a switchport by looking at the MAC address table and just follow the physical wire to find out where it goes?

cheers,

Seb.