Does anyone know how I can obtain the IP address of a device if I know what port on the switch it is. I can get the MAC address knowing the port with a 'show cam dynamic<mod/port>'. So now I know the port and the MAC address, but how can I get the IP associated with it?
Go to the routing device (MSFC/external router) for this host and look at the arp entry for this mac. If this is a Cisco routing device do the following:
"show ip arp H.H.H"
H.H.H 48-bit hardware address of ARP entry
This will give you your IP address.
Hope this helps,
Thanks Don, but the device I am trying get the IP for is on one of our floor switches and we don't have an MSFC on that floor switch. So if I go to my core switch and got the the MSFC there and do the "show ip arp H.H.H", I get an error of "invalid input marker". Anyway, thanks again for your help, any other ideas?
If the MSFC in the Core switch is terminating the VLAN of the access switch you can do it. I suspect you are doing a typo as you wouldn't get that error message if the address is not in the cache. Try this way :-
sh arp | include aaaa.aaaa.aaaa
Andy, what do I put for aaaa.aaaa.aaaa?
Could you give the exact syntax?
Earlier I entered the command as follows and here is the exact error:
afsusssw102msfcb#show ip arp 00-d0-b7-b3-0e-71
Translating "00-d0-b7-b3-0e-71"...domain server (10.40.1.102)
% Invalid input detected at '^' marker.
If you are on a switch , ping the address and then do a "show arp" and it will tell you what you are looking for if this is "not" a trunked setup , if it is a single subnet feeding the 6509 this should work . It will show you the address and the slot/port and the mac address . If you ping the broadcast address for the subnet this will populate the arp table though I not positive this will catch all addresses . Good luck .
Thanks Glen for the response. The only problem is what I am trying to do is be able to get the IP address with only knowing the port and MAC address. I don't know if this is possible...
Assuming your other switch is also a Cisco and everything is default why not try
"show cdp nei det" . The detail info of CDP shows IP addresses. This might get you what you need. I don't see another way with your HW.
No luck there, but thank you Don!
Let me rephrase the question: If I have the following information:
I know the module and port number, eg, 9/26...Can I find out or track down the IP of the device on 9/26?