ADTRAN 1200070L1 - Manual (Page 62)

Chapter 3: Terminal Menu Operation and Structure
46 Express XL/XLT User Manual 61200.070L1-1
IP/Proxy ARP
Write security: 4; Read security: 5
This feature allows the network portion of a group of addresses to be shared
between several physical network segments. The ARP protocol itself provides
a way for devices to create a mapping between physical (i.e., Ethernet) ad-
dresses and logical IP addresses. Proxy ARP makes use of this mapping fea-
ture by instructing a router to answer ARP requests as a “proxy” for the IP
addresses behind one of its ports. The device which sent the ARP request will
then correctly assume that it can reach the requested IP address by sending
packets to the physical address that was returned to it. This technique effec-
tively hides the fact that a network has been (further) subnetted. If this option
is set to Yes (def), when an ARP request is received on the Ethernet port the
address is looked up in the IP routing table. If the forwarding port is not on the
Ethernet port and the route is not the default route, the Express XL/XLT will
answer the request with its own hardware address. If set to No, the Express
XL/XLT will only respond to ARP requests received for its own IP address.