18-3
Catalyst 3560 Switch Software Configuration Guide
78-16156-01
Chapter 18 Configuring DHCP Features
Configuring DHCP Features
Configuring DHCP Features
These sections describe how to configure DHCP snooping and option 82 on your switch:
• Default DHCP Configuration, page 18-3
• DHCP Snooping Configuration Guidelines, page 18-3
• Enabling DHCP Snooping and Option 82, page 18-4
Default DHCP Configuration
Table 18-1 shows the default DHCP configuration.
DHCP Snooping Configuration Guidelines
These are the configuration guidelines for DHCP snooping.
• You must globally enable DHCP snooping on the switch.
• DHCP snooping is not active until DHCP snooping is enabled on a VLAN.
• When you globally enable DHCP snooping on the switch, these Cisco IOS commands are not
available until snooping is disabled. If you enter these commands, the switch returns an error
message, and the configuration is not applied.
–
ip dhcp relay information check global configuration command
–
ip dhcp relay information policy global configuration command
–
ip dhcp relay information trust-all global configuration command
–
ip dhcp relay information trusted interface configuration command
• Before configuring the DHCP information option on your switch, make sure to configure the device
that is acting as the DHCP server. For example, you must specify the IP addresses that the DHCP
server can assign or exclude or configure DHCP options for devices.
–
If your switch is the DHCP server, see the “Configuring the DHCP Server” section on page 4-5
section for more information.
–
If your DHCP server is a Cisco device, refer to the “IP Addressing and Services” section in the
“Configuring DHCP” chapter of the Cisco IOS IP and IP Routing Configuration Guide for
Release 12.1. Otherwise, refer to the documentation that shipped with the server.
Table 18-1 Default DHCP Configuration
Feature Default Setting
DHCP snooping enabled globally Disabled
DHCP snooping information option Enabled
DHCP snooping limit rate None configured
DHCP snooping trust Untrusted
DHCP snooping VLAN Disabled
To Next Page
Loading...
Need help?
General