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If I have two NICs where I know the MAC addresses.

Without logging into the server, how do I figure out which have the IP address

Can arp somehow be used for this?

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up vote 16 down vote accepted

Assuming you're on the same subnet as, ping the address, then run arp -a. That should show your local arp table, including the IP->MAC mapping you're looking for.

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Spot on answer. If you are NOT in the same subnet it can't be done from the outside. You will have to logon to the server itself in that case. – Tonny Nov 3 '11 at 14:33
If the NIC receives its IP address via DHCP, the DHCP server would also have an IP/MAC mapping. – James Sneeringer Nov 3 '11 at 16:20

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