Enabling Dhcp Snooping And Option 82 - Cisco Catalyst 3750-X Software Configuration Manual

Configuring DHCP Features
Command
Step 6
interface range port-range
or
interface interface-id
Step 7
switchport mode access
Step 8
switchport access vlan vlan-id
Step 9
end
Step 10
show running-config
Step 11 copy running-config startup-config
To remove the DHCP packet forwarding address, use the no ip helper-address address interface
configuration command.

Enabling DHCP Snooping and Option 82

Beginning in privileged EXEC mode, follow these steps to enable DHCP snooping on the switch:
Command
Step 1
configure terminal
Step 2 ip dhcp snooping
Step 3 ip dhcp snooping vlan vlan-range
Step 4 ip dhcp snooping information option
Step 5
ip dhcp snooping information option
format remote-id [string ASCII-string |
hostname]
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
24-12
Chapter 24
Purpose
Configure multiple physical ports that are connected
to the DHCP clients, and enter interface range
configuration mode.
or
Configure a single physical port that is connected to
the DHCP client, and enter interface configuration
mode.
Define the VLAN membership mode for the port.
Assign the ports to the same VLAN as configured in
Step 2.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Purpose
Enter global configuration mode.
Enable DHCP snooping globally.
Enable DHCP snooping on a VLAN or range of VLANs. The range is 1
to 4094.
You can enter a single VLAN ID identified by VLAN ID number, a series
of VLAN IDs separated by commas, a range of VLAN IDs separated by
hyphens, or a range of VLAN IDs separated by entering the starting and
ending VLAN IDs separated by a space.
Enable the switch to insert and remove DHCP relay information
(option-82 field) in forwarded DHCP request messages to the DHCP
server. This is the default setting.
(Optional) Configure the remote-ID suboption.
You can configure the remote ID as:
String of up to 63 ASCII characters (no spaces)
•
Configured hostname for the switch
•
If the hostname is longer than 63 characters, it is truncated to 63
Note
characters in the remote-ID configuration.
The default remote ID is the switch MAC address.
Configuring DHCP Features and IP Source Guard
OL-21521-01