Users Guide

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 44. 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
You can configure the number of ARP retries.
The default backoff interval remains at 20 seconds. On the device, the time between ARP resend is
configurable. This timer is an exponential backoff timer. Over the specified period, the time between ARP
requests increases. This time increase reduces the potential for the system to slow down while waiting for a
multitude of ARP responses.
To set and display ARP retries, use the following commands.
• Set the number of ARP retries.
CONFIGURATION mode
arp retries number
The default is 5.
The range is from 1 to 20.
• Set the exponential timer for resending unresolved ARPs.
CONFIGURATION mode
arp backoff-time
The default is 30.
The range is from 1 to 3600.
• Display all ARP entries learned via gratuitous ARP.
EXEC Privilege mode
IPv4 Routing 431