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Proxy ARP

When a node in the attached subnetwork does not have routing or a
default gateway
configured, Proxy ARP can be used to forward ARP
requests to a remote subnetwork.
When the router receives an ARP request
for a remote network and Proxy ARP is enabled, it determines if it has the
best route to the remote network, and then answers the ARP request by
sending its own MAC address to the requesting node. That node then
sends traffic to the router, which in turn uses its own routing table to
forward the traffic to the remote destination.

Basic ARP Configuration

You can use the ARP General configuration menu to specify the timeout
for ARP cache entries, or to enable Proxy ARP for specif ic VLAN
interfaces.
Command Usage
• The aging time determines how long dynamic entries remain the cache.
If the timeout is too short, the router may tie up resources by repeating
ARP requests for addresses recently flushed from the table.
• End stations that require Proxy ARP must view the entire network as
a single network. These nodes must therefore use a smaller subnet
mask than that used by the router or other relevant network devices.
• Extensive use of Proxy ARP can degrade router performance because
it may lead to increased ARP traffic and increased sea rch time for larger
ARP address tables.
norouting,
nodefault
gateway Remote
ARPServer
ProxyARP
ARP
request