User's Manual

Table Of Contents
349
Users Manual of CS-6306R
Chapter 35. DHCP-Snooping Configuration
DHCP-Snooping Configuration 35.1
35.1.1 DHCP-Snooping Configuration Tasks
DHCP-Snooping is to prevent the fake DHCP server from providing the DHCP service by judging the DHCP
packets, maintaining the binding relationship between MAC address and IP address. The L2 switch can
conduct the DAI function and the IP source guard function according to the binding relationship between MAC
address and IP address. The DHCP-snooping is mainly to monitor the DHCP packets and dynamically
maintain the MAC-IP binding list. The L2 switch filters the packets, which do not meet the MAC-IP binding
relationship, to prevent the network attack from illegal users.
Enabling/Disabling DHCP-snooping
Enabling DHCP-snooping in a VLAN
Setting an interface to a DHCP-trusting interface
Enabling DAI in a VLAN
Setting an interface to an ARP-trusting interface
Enabling source IP address monitoring in a VLAN
Setting an interface to the one which is trusted by IP source address monitoring
Configuring the TFTP server for backing up DHCP-snooping binding
Configuring a file name for DHCP-snooping binding backup
Configuring an interval for DHCP-snooping binding backup
Configuring or adding the binding relationship manually
Monitoring and maintaining DHCP-snooping
Examples for DHCP-snooping configuration
35.1.1.1 Enabling/Disabling DHCP-Snooping
Run the following commands in global configuration mode.
Command Purpose
ip dhcp-relay snooping
Enables DHCP snooping.
no ip dhcp-relay snooping Resumes the default settings.
This command is used to enable DHCP snooping in global configuration mode. After this command is run, the
switch is to monitor all DHCP packets and form the corresponding binding relationship.
If the client obtains the address of a switch before this command is run, the switch
cannot add the corresponding binding relationship.