Cisco 7604 User Manual

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Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 37 Configuring DHCP Snooping
Configuring DHCP Snooping
Enabling DHCP Option-82 Data Insertion
To enable DHCP option-82 data insertion, perform this task:
This example shows how to disable DHCP option-82 data insertion:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
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. End with CNTL/Z.
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
Note With the DHCP option-82 on untrusted port feature enabled, the router does not drop DHCP packets that
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 router to which any untrusted
devices are connected.
With Release 12.2(18)SXF1 and later releases, to enable untrusted ports to accept DHCP packets that
include option-82 information, perform this task:
Command Purpose
Step 1
Router(config)# ip dhcp snooping information
option
Enables DHCP option-82 data insertion.
Router(config)# no ip dhcp snooping information
option
Disables DHCP option-82 data insertion.
Step 2
Router(config)# do show ip dhcp snooping |
include 82
Verifies the configuration.
Command Purpose
Step 1
Router(config)# ip dhcp snooping information
option allow-untrusted
(Optional) Enables untrusted ports to accept incoming
DHCP packets with option-82 information.
The default setting is disabled.
Router(config)# no ip dhcp snooping information
option allow-untrusted
Disables the DHCP option-82 on untrusted port feature.
Step 2
Router(config)# do show ip dhcp snooping
Verifies the configuration.

Cisco 7604 Specifications

General

Brand	Cisco
Model	7604
Category	Network Router
Language	English