access wait-request-time
Function
The access wait-request-time dhcpv4 command sets the timeout period for a router to wait for a Request message from a client in response to an Offer message sent to the client.
The undo access wait-request-time dhcpv4 command cancels the setting.
The access wait-request-time dhcpv6 command sets the timeout period for a router to wait for a Request message from a client in response to an Advertise message sent to the client.
The undo access wait-request-time dhcpv6 command cancels the setting.
The default value of the timeout period for a router to wait for a Request message from a client in response to an Offer message sent to the client is 25s, and the default value of the timeout period for a router to wait for a Request message from a client in response to an Advertise message sent to the client is 55s.
This command is supported only on the NetEngine 8000 F1A.
Parameters
| Parameter | Description | Value |
|---|---|---|
| dhcpv4 |
Sets the timeout period for a router to wait for a Request message from a client in response to an Offer message sent to the client. |
- |
| dhcpv6 |
Sets the timeout period for a router to wait for a Request message from a client in response to an Advertise message sent to the client. |
- |
| time-value |
Specifies the timeout period for a router to wait for a Request message from a client. |
The value is an integer ranging from 5 to 60, in seconds. |
Usage Guidelines
Usage Scenario
You are advised to set <time-value> to a value smaller than the default value.
- In user access scenarios, a client sends a Discover message to request an IP address. By default, the timeout period for a router to wait for a Request message from a client in response to an Offer message sent to the client is 25s, which cannot be changed. After the timeout period elapses, the router releases the assigned IPv4 address to the Address Manager (AM) module. To prevent multiple malicious clients from exhausting IPv4 addresses in an address pool by sending DHCPv4 Discover messages, run the wait-request-time <time-value> command to adjust the timeout period for the router to wait for a Request message from a client in response to an Offer message sent to the client.
- In user access scenarios, a client sends a Solicit message to request an IPv6 address. By default, the timeout period for a router to wait for a Request message from a client in response to an Advertise message sent to the client is 55s, which cannot be changed. After the timeout period elapses, the router releases the assigned IPv6 address to the AMv6 module. To prevent multiple malicious clients from exhausting IPv6 addresses in an address pool by sending DHCPv6 Solicit messages, run the access wait-request-time dhcpv6 command to adjust the timeout period for the router to wait for a Request message from a client in response to an Advertise message sent to the client.
Precautions
In VS mode, this command is supported only by the admin VS.
The wait-request-time command is run in the IP address pool view whereas the access wait-request-time dhcpv4 command is run in the system view. When the two commands are both run, the wait-request-time command takes effect. The wait-request-time command is run in the IP address pool view whereas the access wait-request-time dhcpv6 command is run in the system view. When the two commands are both run, the wait-request-time command takes effect.Example
<HUAWEI> system-view [~HUAWEI] access wait-request-time dhcpv4 10
<HUAWEI> system-view [~HUAWEI] access wait-request-time dhcpv6 10