3Com corebuilder 3500 Implementation Manual page 289

However, if the router has ARP proxy enabled, the router answers the
request of Server A with its own MAC address — thus, all traffic sent to
Server B from Server A is addressed to the corresponding IP interface on
the router and forwarded appropriately.
Figure 56 Proxy ARP
Server A
10.10.1.2/255.255.0.0
10.10.1.1/255.255.255.0
10.10.2.1/255.255.255.0
10.10.2.2/255.255.0.0
Server B
With ARP proxy enabled on the router,
the MAC address of IP interface
10.10.1.1 is returned to server A
when server A sends an ARP message
for Server B's MAC address.
ARP Proxy 289