Users Guide

ARP Learning via ARP Request
In Dell EMC Networking OS versions prior to 8.3.1.0, Dell EMC Networking OS learns via ARP requests only if the target IP specied 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 52. ARP Learning via ARP Request
Beginning with Dell EMC 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 53. 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.
Conguring ARP Retries
You can congure the number of ARP retries.
The default backo interval remains at 20 seconds. On the device, the time between ARP resend is congurable. This timer is an
exponential backo timer. Over the specied 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.
IPv4 Routing
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