Configuring DHCPv6-relay

DHCPv6-relay is disabled by default. To enable and configure it, use the commands in this section:



no dhcpv6–relay

Used in the global config context to enable DHCPv6-relay globally on the routing switch.

The no form disables DHCPv6-relay operation on the routing switch.

Default: Disabled


To use DHCPv6-relay on a given VLAN, at least one IPv6 helper-address must be configured on the VLAN, and IPv6 routing (ipv6 unicast–routing) must be enabled.

ipv6 helper–address unicast <ipv6–unicast–helper–addr>

no ipv6 helper–address unicast <ipv6–unicast–helper–addr>

ipv6 helper–address multicast <all–dhcp–servers|ipv6–multicast–helper–addr> egress vlan <vid>

no ipv6 helper–address multicast <all–dhcp–servers|ipv6–multicast–helper–addr> egress vlan <vid>

Used in the VLAN context to enable DHCPv6-relay operation on the VLAN, and to specify either a unicast or multicast DHCPv6-relay Helper address for forwarding DHCPv6 service requests from hosts on the subject VLAN.

ipv6–unicast–helper–addr : Specifies the global unicast address of a remote DHCPv6 server configured to support hosts on the indicated VLAN.

all–dhcp–servers : Specifies that the routing switch forward host requests for DHCPv6 service to multicast address FF05::1:3 via the VLAN specified by egress vlan <vid>

egress vlan <vid> : Specifies the VLAN on which DHCPv6 service requests forwarded to a multicast destination will be relayed. The egress VLAN must be a different VLAN than the one on which the multicast Helper address is configured.

A service request relayed on the egress VLAN to a downstream router remains in that VLAN unless the downstream router is configured on that VLAN with a unicast Helper address for a server on another VLAN. See the example in Figure 20: Routing a multicast DHCPv6 request across a multiple-hop topology.

Using the no form of the command removes the specified Helper address. Removing all Helper addresses from a given VLAN disables DHCPv6-relay on that VLAN.


DHCPv6-relay operation must be enabled with dhcpv6–relay at the global config level.