Reference Guide

IPv4 Routing | 351
In FTOS, Proxy ARP enables hosts with knowledge of the network to accept and forward packets from
hosts that contain no knowledge of the network. Proxy ARP makes it possible for hosts to be ignorant of
the network, including subnetting.
For more information on Proxy ARP, refer to RFC 925,
Multi-LAN Address Resolution, and RFC 1027, Using
ARP to Implement Transparent Subnet Gateways.
Configuration Task List for ARP
The following list includes configuration tasks for ARP:
• Configure static ARP entries (optional)
• Enable Proxy ARP (optional)
• Clear ARP cache (optional)
• ARP Learning via Gratuitous ARP
• ARP Learning via ARP Request
• Configurable ARP Retries
For a complete listing of all ARP-related commands, refer to .
Configure static ARP entries
ARP dynamically maps the MAC and IP addresses, and while most network host support dynamic
mapping, you can configure an ARP entry (called a static ARP) for the ARP cache.
To configure a static ARP entry, use the following command in the CONFIGURATION mode:
These entries do not age and can only be removed manually. To remove a static ARP entry, use the
no arp
ip-address command syntax.
To view the static entries in the ARP cache, use the
show arp static command (Figure 253) in the EXEC
privilege mode.
Command Syntax Command Mode Purpose
arp ip-address mac-address interface CONFIGURATION Configure an IP address and MAC address mapping
for an interface.
•
ip-address: IP address in dotted decimal format
(A.B.C.D).
•
mac-address: MAC address in nnnn.nnnn.nnnn
format
•
interface: enter the interface type slot/port
information.