Server or relay agent IPv6 address-based filtering enables the verification of the advertised DHCPv6 server and relay address in messages with the configured authorized server access list. In DHCPv6 Guard Topology 1 and Topology 2, you can configure the access list to accept DHCPv6 server packets from a specific Source IPv6 address such as a DHCPv6 server or DHCPv6 relay IPv6 address.