DHCPv6 uses what instead of MAC addresses?

• A. DUID - DHCP Unique Identifier
• B. MAC Address
• C. Client Identifier
• D. IP Address

Answer: (A)

DHCPv6 identifies clients with a DHCP Unique Identifier (DUID) rather than using the device’s MAC address. The DUID is carried in the Client Identifier in DHCPv6 messages, and the server uses this identifier to track which IPv6 address and configuration state belongs to which client. This makes client identity stable across events that can change a MAC, such as virtual machines moving between NICs or hardware replacement. Although a DUID can be derived from a MAC address, it’s designed to be a more persistent, unique identifier for DHCP operations. The IP address assigned by DHCPv6 is what the client receives, not what it uses to identify itself.