locate an IP

[sstoppel]

Is there a simple command to allow me to tell what port a given IP is using?

 

[Belushi]

Depend whether or not you are trying to get it from a router or a switch, and if it is a switch whether or not it is a multilayer switch (i.e. - performing routing). From a rotuer you can do the "show ip arp" command to find the MAC address and the port from which it was learned.

If it is a port conencted to a layer 2 switch then you'll need to go onto the switch and run the "show mac-address-table address xxx" command to determine where the mac-address was learned from. The xxx's above refer to the mac-address you learned earlier. It is possible that if you are running an older switch the show mac-address=table command may not work. You'll need a variant of that command if so.

Now there are easier ways even if it is a layer 2 switch where you can get the information from one specific command however it would require you to do DHCP snooping and that would require another conversation.

 

[sstoppel]

4506 switch, with several VLANs. I puzzled it out with ARP and mac address table, but I was hoping for something more expedient.

Thanks for replying!

 

[lerdalt]

Don't forget to use the "| include" options at the end of a show arp or show mac-address-table. I use it all the time if I have the mac-address of a device to track it's IP.