find IP from mac-address

csc010854800 · ‎10-13-2008

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.

Jon Marshall · ‎10-13-2008

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 · ‎10-14-2008

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 · ‎10-14-2008

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.