dhcp speed-limit auto

Function

The dhcp speed-limit auto command enables dynamic rate limiting on DHCP packets.

The undo dhcp speed-limit auto command disables dynamic rate limiting on DHCP packets.

By default, dynamic rate limiting is disabled on DHCP packets.

Format

dhcp speed-limit auto

undo dhcp speed-limit auto

Parameters

None

Views

System view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

To ensure security or facilitate management, users may require that the DHCP packet processing rate should be limited. If the rate is not limited, CPU and memory resources can be used up due to malicious attacks.

Table 1 and Table 2 list the mapping between the DHCP packet rate and CPU/memory usage after dynamic rate limiting on DHCP packets is enabled.

**Table 1** DHCP packet rate and CPU usage
CPU Usage (%)	DHCP Packet Rate (packets/second)
(70–85)	100
[85–100)	50
100	10

**Table 2** DHCP packet rate and memory usage
Memory Usage (%)	DHCP Packet Rate (packets/second)
(65–75)	100
[75–85)	50
[85–100)	10

Prerequisites

DHCP has been enabled globally by using the dhcp enable command.

Precautions

When the CPU usage is higher than 70% or the memory usage is higher than 65%, the DHCP packet processing rate is limited.
The DHCP packet processing rate is the same as the smaller rate among the rates corresponding to the CPU or memory usage. For example, when the CPU usage is 80% and the memory usage is 80%, the DHCP packet rate is 50.

Example

# Enable dynamic rate limiting on DHCP packets.

<HUAWEI> system-view
[HUAWEI] dhcp enable
[HUAWEI] dhcp speed-limit auto