Reference Guide

Security | 1345
ip dhcp relay
c s
Enable Option 82.
Syntax
ip dhcp relay information-option [trust-downstream]
Parameters
Command Modes
CONFIGURATION
Default
Disabled
Command
History
ip dhcp snooping
c s
Enable DHCP Snooping globally.
Syntax
[no] ip dhcp snooping
Command Modes
CONFIGURATION
Default
Disabled
Command
History
Usage
Information
When enabled, no learning takes place until snooping is enabled on a VLAN. Upon disabling
DHCP Snooping the binding table is deleted, and Option 82, IP Source Guard, and Dynamic
ARP Inspection are disabled.
Related
Commands
ip dhcp snooping database
c s
Delay writing the binding table for a specified time.
Syntax
ip dhcp snooping database write-delay minutes
Parameters
Command Modes
CONFIGURATION
trust-downstream
Configure the system to trust Option 82 when it is received from the
previous-hop router.
Version 8.3.7.0 Introduced on S4810
Version 7.8.1.0 Introduced on C-Series and S-Series
Version 8.3.7.0 Introduced on S4810
Version 7.8.1.0 Introduced on C-Series and S-Series
ip dhcp snooping vlan Enable DHCP Snooping on one or more VLANs.
minutes
Range: 5 to 21600