Administrator Guide

ARP
The Dell Networking OS uses two forms of address resolution: address resolution protocol (ARP) and Proxy
ARP.
ARP runs over Ethernet and enables endstations to learn the MAC addresses of neighbors on an IP network.
Over time, the system creates a forwarding table mapping the MAC addresses to their corresponding IP
address. This table is called the ARP Cache and dynamically learned addresses are removed after a defined
period of time.
For more information about ARP, refer to RFC 826, An Ethernet Address Resolution Protocol.
In the Dell Networking OS, 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 about Proxy ARP, refer to RFC 925, Multi-LAN Address Resolution, and RFC 1027, Using
ARP to Implement Transparent Subnet Gateways.
Configuration Tasks for ARP
For a complete listing of all ARP-related commands, refer to the Dell Networking OS Command Line
Reference Guide.
Configuration tasks for ARP include:
• Configuring Static ARP Entries (optional)
• Enabling Proxy ARP (optional)
• Clearing ARP Cache (optional)
• ARP Learning via Gratuitous ARP
• ARP Learning via ARP Request
• Configuring ARP Retries
Configuring 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.
• Configure an IP address and MAC address mapping for an interface.
CONFIGURATION mode
arp ip-address mac-address 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.
IPv4 Routing 457