12.1.3 Rate-limiting DHCP packets
When DHCP snooping is enabled, the Switch discards the DHCP packets that exceed the predetermined reception rate during monitoring of received DHCP packets.
To set the reception rate, use the ip dhcp snooping limit rate configuration command. The reception rate has no limit if a limit has not been set with this command.
When a limit is applied to the DHCP packet reception rate, the limit is applied to all DHCP packets received by the Switch.
DHCP packets exceeding the rate are discarded, and the incident is logged in the operation log. However, it does not send SNMP notifications. To check the information in the operation log, execute the show ip dhcp snooping logging operation command.
- <Structure of this section>
(1) Trigger for collecting operation log information
The operation log records Limit Exceeded events.A Limit Exceeded event occurs when the configured reception rate is exceeded.
For 30 seconds after a Limit Exceeded event is logged, no events will be logged, even if packets are discarded, because the rate has been exceeded.
The following figure shows the point at which a Limit Exceeded event for the DHCP packet reception rate is logged in the operation log.
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![[Figure Data]](./GRAPHICS/ZU216060.GIF)