But discards all the DHCP Offer message from UNTRUST port, then we set legal DHCP Server
connected port as TRUST port, and the other port set as UNTRUST port, this can realize the shielding
of illegal DHCP Server.
1-1
As shown in diagram 1-1 network environment. The Client obtain IP address and surf the Internet
through legal DHCP Server. Set the switch port connected by client as untrust port according to the
requirement, set the switch port connected by DHCP Server as trust port. So we can put an end to the
affect to other user that private set up illegal DHCP Server user caused.
13.2.
DHCP Snooping Configuration
13.2.1. Enabling DHCP Snooping
Only after enabling the DHCP Snooping, DHCP Snooping function will take effect, the configured
trusted port and untrusted port can work properly.
Command
Function
Switch(config)#
dhcp-snooping
Enable DHCP Snooping, DHCP Snooping
is disabled by default.
Enabling DHCP Snooping in global configuration mode:
Switch# configure terminal
Switch(config)#
dhcp-snooping
Global DHCP mode: enable
13.2.2. Trusted Port Configuration
Use the following command to configure DHCP Snooping trusted port in interface configuration mode:
