Administrator Guide
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
The system learns via ARP requests only if the target IP specied 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 54. ARP Learning via ARP Request
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 55. 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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