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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.
These entries do not age and can only be removed manually. To remove a static ARP entry, use the no arp ip-address
command.
To view the static entries in the ARP cache, use the show arp static command in EXEC privilege mode.
Dell#show arp
Protocol Address Age(min) Hardware Address Interface VLAN CPU
-----------------------------------------------------------------------------------------
Internet 10.11.68.14 94 00:01:e9:45:00:03 Ma 0/0 - CP
Internet 10.11.209.254 0 00:01:e9:45:00:03 Ma 0/0 - CP
Dell#
Enabling Proxy ARP
By default, Proxy ARP is enabled. To disable Proxy ARP, use the no proxy-arp command in the interface mode.
To re-enable Proxy ARP, use the following command.
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IPv4 Routing