General operating notes for DHCPv6

  • If multiple DHCPv6 servers are available, the switch selects a server based on the preference value sent in DHCPv6 messages from the servers.

  • The switch supports both DHCPv4 and DHCPv6 client operation on the same VLAN.

  • With IPv6 enabled, the switch determines the default IPv6 router for the VLAN from the RAs it receives. See Default IPv6 router.

  • DHCPv6 and statically configured global unicast addresses are mutually exclusive on a given VLAN. That is, configuring DHCPv6 on a VLAN erases any static global unicast addresses previously configured on that VLAN, and the reverse. (A statically configured link-local address is not affected by configuring DHCPv6 on the VLAN.)

  • For the same subnet on the switch, a DHCPv6 global unicast address assignment takes precedence over an autoconfigured address assignment, regardless of which address type was the first to be configured. If DHCPv6 is subsequently removed from the configuration, an autoconfigured address assignment replaces it after the next RA is received on the VLAN. DHCPv6 and autoconfigured addresses coexist on the same VLAN if they belong to different subnets.

For related information, see:
  • RFC 3315: "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)"

  • RFC 3633: "IPv6 Prefix Options for Dynamic Host Configuration Protocol (DHCP) version 6"

  • RFC 3736: "Stateless Dynamic Host Configuration Protocol (DHCP) Service for IPv6"