Cisco IE 3000 User Manual

20-9
Cisco IE 3000 Switch Software Configuration Guide
OL-13018-01
Chapter 20 Configuring DHCP Features
Configuring DHCP Features
To disable the DHCP server and relay agent, use the no service dhcp global configuration command.
See the “Configuring DHCP” section of the “IP Addressing and Services” section of the Cisco IOS IP
Configuration Guide, Release
12.2 from the Cisco.com page under Documentation > Cisco IOS
Software > 12.2 Mainline > Configuration Guides for these procedures:
• Checking (validating) the relay agent information
• Configuring the relay agent forwarding policy
Enabling DHCP Snooping and Option 82
Beginning in privileged EXEC mode, follow these steps to enable DHCP snooping on the switch:
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
ip dhcp snooping Enable DHCP snooping globally.
Step 3
ip dhcp snooping vlan vlan-range 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.
Step 4
ip dhcp snooping information option 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.
Step 5
ip dhcp snooping information option
allow-untrusted
(Optional) If the switch is an aggregation switch connected to an edge
switch, enable the switch to accept incoming DHCP snooping packets
with option-82 information from the edge switch.
The default setting is disabled.
Note Enter this command only on aggregation switches that are
connected to trusted devices.
Step 6
interface interface-id Specify the interface to be configured, and enter interface configuration
mode.
Step 7
ip dhcp snooping trust (Optional) Configure the interface as trusted or untrusted. You can use the
no keyword to configure an interface to receive messages from an
untrusted client. The default setting is untrusted.
Step 8
ip dhcp snooping limit rate rate (Optional) Configure the number of DHCP packets per second that an
interface can receive. The range is 1 to 2048. By default, no rate limit is
configured.
Note We recommend an untrusted rate limit of not more than 100
packets per second. If you configure rate limiting for trusted
interfaces, you might need to increase the rate limit if the port is
a trunk port assigned to more than one VLAN on which DHCP
snooping is enabled.
Step 9
exit Return to global configuration mode.

Cisco IE 3000 Specifications

General

Brand	Cisco
Model	IE 3000
Category	Switch
Language	English