Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.100.0 - Page 409

• For a VLAN interface, enter the keyword vlan then a number from 1 to 4094. NOTE: Transit traffic may not be forwarded during the period when deleted ARP entries are resolved again and re-installed in CAM. Use this option with extreme caution. ARP Learning via Gratuitous ARP Gratuitous ARP can mean an ARP request or reply. In the context of ARP learning via gratuitous ARP on Dell Networking OS, the gratuitous ARP is a request. A gratuitous ARP request is an ARP request that is not needed according to the ARP specification, but one that hosts may send to: • detect IP address conflicts • inform switches of their presence on a port so that packets can be forwarded • update the ARP table of other nodes on the network in case of an address change 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 Networking OS versions prior to 8.3.1.0, Dell 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 48. 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. IPv4 Routing 409