Enabling autoconfiguration of a global unicast address and a default router identity on a VLAN

Enabling automatic configuration or rebooting the switch with autoconfig enabled on a VLAN causes the switch to configure IPv6 addressing on the VLAN using RAs and an EUI-64 interface identifier.

Syntax:

ipv6 address autoconfig

no ipv6 address autoconfig

Implements unicast address autoconfiguration as follows:

  • If IPv6 is not already enabled on the VLAN, enables IPv6 and generates a link-local EUI-64 address.

  • Generates router solicitations (RS) on the VLAN.

  • If an RA is received on the VLAN, the switch uses the route prefix in the RA to configure a global unicast address. Interface identifier for this address is the same as the interface identifier used in the current link-local address at the time the RA is received. It can be either a statically configured or the (automatic) EUI-64 interface identifier, depending on how the link-local address was configured.If an RA is not received on the VLAN after autoconfig is enabled, a link-local address is present, but no global unicast addresses are autoconfigured.
    NOTE:

    If a link-local address is already configured on the VLAN, a later autoconfigured global unicast address will use the same interface identifier as the link-local address.

    Autoconfigured and DHCPv6-assigned global unicast addresses with the same prefix are mutually exclusive on a VLAN. On a given switch, if both options are configured on the same VLAN, only the first to acquire a global unicast address is used.

After verification of uniqueness by DAD, an IPv6 address assigned to a VLAN by autoconfiguration is set to the preferred and valid lifetimes specified by the RA used to generate the address and is configured as a preferred address.

Default: Disabled.

The no form of the command produces different results, depending on how IPv6 is configured on the VLAN: If enabled only by the autoconfig command, deleting this command disables IPv6 on the VLAN.