Command Attributes
• Timeout – Sets the aging time for dynamic entries i n the ARP cach e.
(Range: 300 - 86400 seconds; Default: 1200 seconds or 2 0 minutes)
The ARP aging timeout can be set for any currently configured VLAN.
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.
When a ARP entry expires, it is deleted from the cache and an ARP request packet
is sent to re-establish the MAC address.
• Proxy ARP – Enables or disables Proxy ARP for specif ied VLAN inte rfaces ,
allowing a non-routing device to determine the MAC address of a host on anothe r
subnet or network. (Default: Disabled)
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 tha t used
by the router or other relevant networ k devices.
Extensive use of Proxy ARP can degrade router performance because it may lead
to increased ARP traffic and increased search time for larger ARP addre ss tab les.

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Basic ARP Configuration
You can use the ARP General configuration menu to specify the timeout for AR P
cache entries, or to enable Proxy ARP for specific VLAN interfaces.
Command Usage
Proxy ARP
When a node in the attached subnetwork does not have routing or a defau lt ga te way
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 rout e to the remot e network, and then
answers the ARP request by sending its own MAC address to the req uestin g 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.
Proxy ARP
ARP
request
no routing,
no default
gateway
Remote
A
RP Server
Address Resolution Protocol

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