ack-flood threshold
Use ack-flood threshold to set the global threshold for triggering ACK flood attack prevention.
Use undo ack-flood threshold to restore the default.
Syntax
ack-flood threshold threshold-value
undo ack-flood threshold
Default
The global threshold is 1000 for triggering ACK flood attack prevention.
Views
Attack defense policy view
Predefined user roles
network-admin
mdc-admin
Parameters
threshold-value: Specifies the threshold value. The value range is 1 to 1000000 in units of ACK packets sent to an IP address per second.
Usage guidelines
With global ACK flood attack detection configured, the device is in attack detection state. When the sending rate of ACK packets to an IP address reaches the threshold, the device enters prevention state and takes the specified actions. When the rate is below the silence threshold (three-fourths of the threshold), the device returns to the attack detection state.
The global threshold applies to global ACK flood attack detection. Adjust the threshold according to the application scenarios. If the number of ACK packets sent to a protected server, such as an HTTP or FTP server, is normally large, set a large threshold. A small threshold might affect the server services. For a network that is unstable or susceptible to attacks, set a small threshold.
Examples
# Set the global threshold to 100 for triggering ACK flood attack prevention in attack defense policy atk-policy-1.
<Sysname> system-view [Sysname] attack-defense policy atk-policy-1 [Sysname-attack-defense-policy-atk-policy-1] ack-flood threshold 100
Related commands
ack-flood action
ack-flood detect
ack-flood detect non-specific