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If the host, for which an ARP table entry is present on the connected router, has changed its NIC(so that its MAC address has changed), what will happen when a packet is sent out on the link with the old MAC address by the router?

Will any kind of error message(like ICMP) be generated at layer2/3? If yes, what will be its SIP and DIP?

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Matches between MAC and IP are stores in the ARP cache. Unless you manually created a static entry these will time out. The time out period depends on your OS. (For modern windows installs this takes about 30 seconds according to ). So nothing abnormal will happen if you can wait a short period after changing the NIC. (Not posted as an answer since I do not actually know what will happen if you do try this before the time out. I suspect it will depend on the operating systems involved. Or more precisely, on the used TCP/IP stack). – Hennes Jun 10 '12 at 14:39

Nothing will happen, the packet will be "lost", and time-out.

Depending on the implementation, the router will then try with arp again, get the new mac and then send the next* packet to the new address.

*with tcp, the lost packets will be retransmitted, with udp, it depends on the higher protocol (l7) - usually not

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