Enabling Dhcp Option-82 Data Insertion; Enabling The Dhcp Option 82 On Untrusted Port Feature - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Configuring DHCP Snooping

Enabling DHCP Option-82 Data Insertion

To enable DHCP option-82 data insertion, perform this task:
Command
Step 1
Router(config)# ip dhcp snooping information
option
Router(config)# no ip dhcp snooping information
option
Step 2
Router(config)# do show ip dhcp snooping |
include 82
This example shows how to disable DHCP option-82 data insertion:
Router# configure terminal
Enter configuration commands, one per line.
Router(config)# no ip dhcp snooping information option
Router(config)# do show ip dhcp snooping | include 82
Insertion of option 82 is disabled
Router#(config)
This example shows how to enable DHCP option-82 data insertion:
Router# configure terminal
Enter configuration commands, one per line.
Router(config)# ip dhcp snooping information option
Router(config)# do show ip dhcp snooping | include 82
Insertion of option 82 is enabled
Router#(config)

Enabling the DHCP Option 82 on Untrusted Port Feature

With the DHCP option 82 on untrusted port feature enabled, the switch does not drop DHCP packets that
Note
include option-82 information that are received on untrusted ports. Do not enter the ip dhcp snooping
information option allowed-untrusted command on an aggregation switch to which any untrusted
devices are connected.
To enable untrusted ports to accept DHCP packets that include option-82 information, perform this task:
Command
Step 1
Router(config)# ip dhcp snooping information
option allow-untrusted
Router(config)# no ip dhcp snooping information
option allow-untrusted
Step 2
Router(config)# do show ip dhcp snooping
Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
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Chapter 34
Purpose
Enables DHCP option-82 data insertion.
Disables DHCP option-82 data insertion.
Verifies the configuration.
End with CNTL/Z.
End with CNTL/Z.
Purpose
(Optional) Enables untrusted ports to accept incoming
DHCP packets with option-82 information.
The default setting is disabled.
Disables the DHCP option 82 on untrusted port feature.
Verifies the configuration.
Configuring DHCP Snooping
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