Справочник Пользователя для Cisco Systems 3130
21-8
Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter 21 Configuring DHCP Features and IP Source Guard
Configuring DHCP Features
DHCP Snooping and Switch Stacks
DHCP snooping is managed on the stack master. When a new switch joins the stack, the switch receives
the DHCP snooping configuration from the stack master. When a member leaves the stack, all DHCP
snooping address bindings associated with the switch age out.
the DHCP snooping configuration from the stack master. When a member leaves the stack, all DHCP
snooping address bindings associated with the switch age out.
All snooping statistics are generated on the stack master. If a new stack master is elected, the statistics
counters reset.
counters reset.
When a stack merge occurs, all DHCP snooping bindings in the stack master are lost if it is no longer
the stack master. With a stack partition, the existing stack master is unchanged, and the bindings
belonging to the partitioned switches age out. The new master of the partitioned stack begins processing
the new incoming DHCP packets. For more information about switch stacks, see
the stack master. With a stack partition, the existing stack master is unchanged, and the bindings
belonging to the partitioned switches age out. The new master of the partitioned stack begins processing
the new incoming DHCP packets. For more information about switch stacks, see
Configuring DHCP Features
These sections contain this configuration information:
•
•
•
•
•
•
•
•
•
•
Default DHCP Configuration
shows the default DHCP configuration.
Table 21-1
Default DHCP Configuration
Feature
Default Setting
DHCP server
Enabled in Cisco IOS software, requires
configuration
configuration
1
DHCP relay agent
Enabled
2
DHCP packet forwarding address
None configured
Checking the relay agent information
Enabled (invalid messages are dropped)
DHCP relay agent forwarding policy
Replace the existing relay agent information
DHCP snooping enabled globally
Disabled
DHCP snooping information option
Enabled