Abstract: The invention ensures that a single and consistent reply is made to ARP request in a system of connected IP networks. When an adapter (A) becomes active, the owning host sends an ARP advertisement into the network over the adapter. If the advertisement is also received at the sending host over a different adapter B, then the host knows that adapter B is on in the same physical network as adapter A and B can be designated as a backup adapter for A and A can be designated as backup adapter for B. If adapter A fails or becomes inactive, the host resets the backup adapter field for any adapter it owns for which A is marked as the backup adapter. If a backup adapter B has been designated for A, the host also sends an ARP advertisement associating MAC-B with IP-A. This allows network connections originally served via adapter A to continue non-disruptively over adapter B and it also provides access to the host for subsequent new connections.

Abstract: The invention ensures that a single and consistent reply is made to ARP requests in a system of connected IP networks in which each host can contain combinations of host adapters, offload adapters and virtual IP addresses.