CLI Reference Guide-R07

Chapter 27 | IP Interface Commands
IPv6 Interface
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◆ 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.
Example
The following configures five neighbor solicitation attempts for addresses
configured on VLAN 1. The show ipv6 interface command indicates that the
duplicate address detection process is still on-going.
Console(config)#interface vlan 1
Console(config-if)#ipv6 nd dad attempts 5
Console(config-if)#end
Console#show ipv6 interface
VLAN 1 is up
IPv6 is enabled
Link-local address:
fe80::200:e8ff:fe90:0/64
Global unicast address(es):
2009:db9:2229::79, subnet is 2009:db9:2229:0::/64
Joined group address(es):
ff01::1/16
ff02::1/16
ff02::1:ff00:79/104
ff02::1:ff90:0/104
IPv6 link MTU is 1500 bytes.
ND DAD is enabled, number of DAD attempts: 5.
ND retransmit interval is 1000 milliseconds
ND advertised retransmit interval is 0 milliseconds
ND reachable time is 30000 milliseconds
ND advertised reachable time is 0 milliseconds
ND advertised router lifetime is 1800 seconds
Console#
Related Commands
ipv6 nd ns-interval (681)
show ipv6 neighbors (683)