ECS4100 Series CLI Reference Guide-R07

Chapter 9 | General Security Measures
DHCPv4 Snooping
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Command Mode
Global Configuration
Command Usage
◆ When DHCP snooping is enabled globally using the ip dhcp snooping
command, and enabled on a VLAN with this command, DHCP packet filtering
will be performed on any untrusted ports within the VLAN as specified by the ip
dhcp snooping trust command.
◆ When the DHCP snooping is globally disabled, DHCP snooping can still be
configured for specific VLANs, but the changes will not take effect until DHCP
snooping is globally re-enabled.
◆ When DHCP snooping is globally enabled, and then disabled on a VLAN, all
dynamic bindings learned for this VLAN are removed from the binding table.
Example
This example enables DHCP snooping for VLAN 1.
Console(config)#ip dhcp snooping vlan 1
Console(config)#
Related Commands
ip dhcp snooping (323)
ip dhcp snooping trust (334)
ip dhcp snooping
information option
carry-to-client
This command enables option 82 to be carried to the client. Use the no form
disable option 82 carrying to the client.
Syntax
[no] ip dhcp snooping information option carry-to-client
Default Setting
Disabled
Command Mode
Interface Configuration (Ethernet, Port Channel)
Example
Console(config)#interface ethernet 1/1
Console(config-if)#ip dhcp snooping information option carry-to-client
Console(config-if)#