Administrator Guide

In the request, the host uses its own IP address in the Sender Protocol Address and Target Protocol Address fields.
Enabling ARP Learning via Gratuitous ARP
To enable ARP learning via gratuitous ARP, use the following command.
• Enable ARP learning via gratuitous ARP.
CONFIGURATION mode
arp learn-enable
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 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 43. 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 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.
IPv4 Routing
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