Client IP-to-MAC address mappings

Client IP addresses need not be on directly connected networks, as long as the client MAC address is learned on the client port and the client port is on the same VLAN as the DHCP server port. In this case, the system learns the client IP-to-MAC port mapping. Therefore, a VLAN with DHCP snooping enabled does not require a VE interface.

In earlier releases, in the Layer 3 software image, DHCP snooping did not learn the secure IP-to-MAC address mapping for a client, if the client port was not a Virtual Ethernet (VE) interface with an IP subnet address. In other words, the client IP address had to match one of the subnets of the client port in order for DHCP to learn the address mapping.