Users Guide
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 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 47. 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 48. 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.
Conguring ARP Retries
In Dell Networking OS versions prior to 8.3.1.0, the number of ARP retries is set to ve and is not congurable. After ve retries, Dell
Networking OS backs o 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 congurable.
The default backo interval remains at 20 seconds. On the device, the time between ARP resend is congurable. This timer is an
exponential backo timer. Over the specied 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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