find IP from mac-address

Unanswered Question
Oct 13th, 2008

is there any way to find the IP address from the mac-address when the mac-address is 4 or 5 hops away from my router.

I have this problem too.
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Jon Marshall Mon, 10/13/2008 - 23:33

If you mean find the IP address from the mac-address by interrogating your router then the answer is no.

Mac-addresses are only local to the LAN so if the device is 4 or 5 hops away it the packet on your router will only have the mac-address of the last hop.

Jon

csc010854800 Tue, 10/14/2008 - 00:02

HOST 1----R1--R2--R3-----R4-----R5---HOST 2

please clarify , if i have a mac-address of HOST 2 , then which Router will be the last hop for HOST 1 ...... and the command for that ???

Mo'ath Al Rawashdeh Tue, 10/14/2008 - 00:55

For your scenario above, you can know the IP address of Host2 from the MAC by issuing the "R5# show arp" command on router 5 only, as this router is the default gateway for Host2.

Cheers mate.

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