cisco switches caching IP's to MAC's for 3 hours

abefroman · 11-01-2006, 02:04 PM

My cisco switches caching IP's to MAC's for 3 hours

I have a cisco 5500 master switch connected to a cisco 2950 switch.

If I remove an IP form a server on on port of my 2950 and add it to another server on that switch, the IP does not resolve for 3 hours. After 3 hours the IP resolves ok.

It appears the switch associated a MAC address with that IP and it caches that for 3 hours.

I know how to show and clear the mac address table, but is there a MAC to IP table?

What could be going on here?

acid_kewpie · 11-01-2006, 04:07 PM

without seeing more of your config i can't think of any reason that should happen, but i'd expect that you have a fairly non standard port config on the 2950 if those ports are being used for servers and not uplinks to other switches.

the ip to mac table is the arp cache, "sh arp". the other useful table is "sh mac-address-table" but i'd have thought you'd be much more familiar with arp tables already comapred to the mac table.

abefroman · 11-01-2006, 09:40 PM

Thanks, thats the command I needed, it doesnt do much good without | include

abefroman · 11-01-2006, 09:41 PM

Do you know if there is a not include?

The equivlent to | grep -v in linx