Interface Configuration (VLAN)
Configuring a value of 0 disables duplicate address detection.
Duplicate address detection determines if a new unicast IPv6 address already
exists on the network before it is assigned to an interface.
Duplicate address detection is stopped on any interface that has been
suspended (see the
IPv6 addresses assigned to that interface are placed in a "pending" state.
Duplicate address detection is automatically restarted when the interface is
An interface that is re-activated restarts duplicate address detection for all
unicast IPv6 addresses on the interface. While duplicate address detection is
performed on the interface's link-local address, the other IPv6 addresses remain
in a "tentative" state. If no duplicate link-local address is found, duplicate
address detection is started for the remaining IPv6 addresses.
If a duplicate address is detected, it is set to "duplicate" state, and a warning
message is sent to the console. If a duplicate link-local address is detected, IPv6
processes are disabled on the interface. If a duplicate global unicast address is
detected, it is not used. All configuration commands associated with a
duplicate address remain configured while the address is in "duplicate" state.
If the link-local address for an interface is changed, duplicate address detection
is performed on the new link-local address, but not for any of the IPv6 global
unicast addresses already associated with the interface.
The following configures five neighbor solicitation attempts for addresses
configured on VLAN 1. The
duplicate address detection process is still on-going.
Console(config)#interface vlan 1
Console(config-if)#ipv6 nd dad attempts 5
Console#show ipv6 interface
VLAN 1 is up
IPv6 is stalled.
Global unicast address(es):
2009:DB9:2229::79, subnet is 2009:DB9:2229:0::/64 [TENTATIVE]
Joined group address(es):
command). While an interface is suspended, all unicast
show ipv6 interface
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| IP Interface Commands
command indicates that the