6.9.5 Example for Configuring DHCP Rate Limit
This section describes how to configure the highest rate at which DHCP packets are sent to the
protocol stack and the alarm function of DHCP rate limit.
Networking Requirements
As shown in
, a department uses Router A to directly connect the client. Hosts in this
department function as DHCP clients and are assigned IP addresses by the DHCP server. If the
attacker sends a large number of DHCP packets to Router A, the CPU resources of Router A
will become insufficient. As a result, the requests of authorized users cannot be processed in
time. To avoid this problem, network administrators limit the rate at which DHCP packets are
sent to Router A. This allows Router A to effectively defend against DHCP attack packets, and
to process requests of authorized users in time.
Figure 6-9
Networking diagram for configuring the DHCP relay
DHCP Server
Internet
DHCP
Client
DHCP
Client
Attacker
DHCP Relay
RouterB
RouterA
Configuration Roadmap
The configuration roadmap is as follows:
l
Configure the highest rate at which DHCP packets are sent to Router A in the system view.
This allows Router A to limit the rate at which DHCP packets are received within a normal
range.
Data Preparation
1.
Highest rate at which DHCP packets are sent to the protocol stack: 90 pps
2.
Alarm threshold: 80
Huawei AR150&200 Series Enterprise Routers
Configuration Guide - IP Service
6 DHCP Configuration
Issue 02 (2012-03-30)
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