Administrator Guide

CONFIGURATION mode
arp learn-enable
ARP Learning via ARP Request
In Dell Networking OS versions prior to 8.3.1.0, Dell Networking OS learns via ARP requests only if the target IP specified in
the packet matches the IP address of the receiving router interface. This is the case when a host is attempting to resolve the
gateway address.
If the target IP does not match the incoming interface, the packet is dropped. If there is an existing entry for the requesting
host, it is updated.
Figure 36. ARP Learning via ARP Request
Beginning with Dell Networking OS version 8.3.1.0, when you enable ARP learning via gratuitous ARP, the system installs a new
ARP entry, or updates an existing entry for all received ARP requests.
Figure 37. ARP Learning via ARP Request with ARP Learning via Gratuitous ARP Enabled
Whether you enable or disable ARP learning via gratuitous ARP, the system does not look up the target IP. It only updates the
ARP entry for the Layer 3 interface with the source IP of the request.
Configuring ARP Retries
In Dell Networking OS versions prior to 8.3.1.0, the number of ARP retries is set to five and is not configurable. After five retries,
Dell Networking OS backs off for 20 seconds before it sends a new request. Beginning with Dell Networking OS version 8.3.1.0,
the number of ARP retries is configurable.
The default backoff interval remains at 20 seconds.
To set and display ARP retries, use the following commands.
IPv4 Routing
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