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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 45 Configuring DHCP Snooping, IP Source Guard, and IPSG for Static Hosts Configuring DHCP Snooping
Enabling DHCP Snooping on the Aggregration Switch, page 45-9
Enabling DHCP Snooping and Option 82, page 45-10
Enabling DHCP Snooping on Private VLAN, page 45-12
Configuring DHCP Snooping on Private VLAN, page 45-12
Configuring DHCP Snooping with an Ethernet Channel Group, page 45-12
Enabling the DHCP Snooping Database Agent, page 45-13
Limiting the Rate of Incoming DHCP Packets, page 45-13
Configuration Examples for the Database Agent, page 45-15
Note For DHCP server configuration information, refer to “Configuring DHCP” in the Cisco IOS IP and IP
Routing Configuration Guide at:
http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfdhcp.html
Default Configuration for DHCP Snooping
DHCP snooping is disabled by default. Table 4 5-1 shows all the default configuration values for each
DHCP snooping option.
If you want to change the default configuration values, see the “Enabling DHCP Snooping” section.
Enabling DHCP Snooping
Note When DHCP snooping is enabled globally, DHCP requests are dropped until the ports are configured.
Consequently, you should probably configure this feature during a maintenance window and not during
production.
Table 45-1 Default Configuration Values for DHCP Snooping
Option Default Value/State
DHCP snooping Disabled
DHCP snooping information option Enabled
DHCP snooping information option
allow-untrusted Disabled
DHCP snooping limit rate Infinite (functions as if rate limiting were disabled)
DHCP snooping trust Untrusted
DHCP snooping vlan Disabled