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Command
History
Version Description
9.9(0.0) Introduced on the FN IOM.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
Related
Commands
show ip dhcp snooping — displays the contents of the DHCP binding table.
ip dhcp relay
Enable Option 82.
Syntax
ip dhcp relay information-option [trust-downstream]
Parameters
trust-
downstream
Configure the system to trust Option 82 when it is received from the previous-hop
router.
Defaults Disabled.
Command Modes CONFIGURATION
Supported Modes Full–Switch
Command
History
Version Description
9.9(0.0) Introduced on the FN IOM.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
ip dhcp snooping
Enable DHCP Snooping globally.
Syntax
[no] ip dhcp snooping
Defaults Disabled.
Command Modes CONFIGURATION
Supported Modes Full–Switch
Command
History
Version Description
9.9(0.0) Introduced on the FN IOM.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
Usage
Information
When enabled, no learning takes place until you enable snooping on a VLAN. After 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 vlan — enables DHCP Snooping on one or more VLANs.
ip dhcp snooping database
Delay writing the binding table for a specified time.
Syntax
ip dhcp snooping database write-delay minutes
Parameters
minutes The range is from 5 to 21600.
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