The ipv6 nd dad attempts command configures the number of times the neighbor sends the request messages during the system performs DAD.
The undo ipv6 nd dad attempts command restores the default configuration.
By default, one NS message is sent when DAD is performed.
| Parameter | Description | Value |
|---|---|---|
value |
Specifies the number of times of Duplicate Address Detection (DAD) attempts. |
It is an integer ranging from 0 to 600. The default value is 1. |
Ethernet interface view, Eth-Trunk interface view, Tunnel interface view, VLANIF interface view, BDIF interface view
Usage Scenario
When you configure an IPv6 address (a global unicast address or a link-local address) for an interface, the system needs to check whether other interfaces connected to this interface have already used the IPv6 address to be configured. This is to prevent address conflicts. The default number of detection times is recommended. If there is a long link delay, you can increase the number of detection times. When a loopback address is configured for an interface, the loopback address may fail the address conflict detection. In this case, you can set the number of detection times to 0 to disable detection, allowing the loopback address to be used.
Prerequisites
The ipv6 enable command has been run in the interface to enable IPv6.
Configuration Impact
If the number of NS messages that are sent during the DAD process is set to 0, DAD is prohibited.
Precautions
If the physical link connected to an interface fails, DAD cannot be performed on the interface. If DAD fails, the IPv6 protocol status of the interface changes to Down. You need to run the shutdown and undo shutdown commands on the interface to restore the status.
If the ipv6 nd dad attempts command has been run, running the ipv6 nd ra command will change the number of configured detection times.
DAD transmits node configuration variables (as specified in RFC 2462, IPv6 Stateless Address Auto Configuration). The system automatically determines the time to send neighbor request messages while DAD is performed to detect a tentative unicast IPv6 address.