proxy ARP
<networking> The technique in which one {host}, usually a
{router}, answers {Address Resolution Protocol} (ARP) requests
intended for another machine. By "faking" its identity, the
router accepts responsibility for routing {packets} to the
"real" destination. Proxy ARP allows a site to use a single
{IP address} with two physical networks. {Subnet}ting would
normally be a better solution.
(2007-09-03)