The ipv6 nd neighbor-limit command configures the maximum number of dynamic neighbor entries allowed by an interface.
The undo ipv6 nd neighbor-limit command cancels the configuration.
By default, the maximum number of dynamic neighbor entries allowed by an interface is not configured.
| Parameter | Description | Value |
|---|---|---|
| max-number |
Specifies the maximum number of dynamic neighbor entries allowed by an interface. |
The value is an integer ranging from 0 to 65536. The value range of this parameter is controlled by the PAF. After the PAF is loaded, the value range of this parameter is from 0 to 147456. |
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Usage Scenario
Upon receipt of a large number of RA messages from an attacker, a device learns dynamic neighbor entries, which consumes high CPU and memory resources. To defend against RA flooding attacks, run the ipv6 nd neighbor-limit command to configure the maximum number of dynamic neighbor entries allowed by an interface.
When the number of dynamic neighbor entries exceeds a specified threshold, a large amount of redundant information exists, and the device stops recording. In this case, you can run the reset ipv6 neighbors command to clear specified dynamic neighbor entries. However, this operation may affect IPv6 packet forwarding. Exercise caution when you perform this operation. Setting the max-number parameter to 0 equals to running the undo ipv6 nd neighbor-limit [ max-number ] command.Prerequisites
Before running this command, run the ipv6 enable command in the interface view to enable the IPv6 function.