Dell PowerEdge FN I/O Module Configuration Guide 9.10(0.0)

In the Dell Networking OS versions prior to 8.3.1.0, the system 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 1. ARP Learning via ARP Request

Beginning with the 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 2. 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.