Cisco Systems 3560 Manual De Usuario
21-14
Catalyst 3560 Switch Software Configuration Guide
OL-8553-06
Chapter 21 Configuring DHCP Features and IP Source Guard
Configuring DHCP Snooping
Enabling the Cisco IOS DHCP Server Database
For procedures to enable and configure the Cisco IOS DHCP server database, see the “DHCP
Configuration Task List” section in the “Configuring DHCP” chapter 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.
Configuration Task List” section in the “Configuring DHCP” chapter 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.
Enabling the DHCP Snooping Binding Database Agent
Beginning in privileged EXEC mode, follow these steps to enable and configure the DHCP snooping
binding database agent on the switch:
binding database agent on the switch:
To stop using the database agent and binding files, use the no ip dhcp snooping database global
configuration command. To reset the timeout or delay values, use the ip dhcp snooping database
timeout seconds or the ip dhcp snooping database write-delay seconds global configuration
command.
configuration command. To reset the timeout or delay values, use the ip dhcp snooping database
timeout seconds or the ip dhcp snooping database write-delay seconds global configuration
command.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
ip dhcp snooping database
{flash:/filename |
ftp://user:password@host/filename |
http://[[username:password]@]{hostna
me | host-ip}[/directory]
{flash:/filename |
ftp://user:password@host/filename |
http://[[username:password]@]{hostna
me | host-ip}[/directory]
/image-name.tar |
rcp://user@host/filename}|
tftp://host/filename
rcp://user@host/filename}|
tftp://host/filename
Specify the URL for the database agent or the binding file by using one
of these forms:
of these forms:
•
flash:/filename
•
ftp://user:password@host/filename
•
http://[[username:password]@]{hostname | host-ip}[/directory]
/image-name.tar
•
rcp://user@host/filename
•
tftp://host/filename
Step 3
ip dhcp snooping database timeout
seconds
seconds
Specify (in seconds) how long to wait for the database transfer process to
finish before stopping the process.
finish before stopping the process.
The default is 300 seconds. The range is 0 to 86400. Use 0 to define an
infinite duration, which means to continue trying the transfer
indefinitely.
infinite duration, which means to continue trying the transfer
indefinitely.
Step 4
ip dhcp snooping database write-delay
seconds
seconds
Specify the duration for which the transfer should be delayed after the
binding database changes. The range is from 15 to 86400 seconds. The
default is 300 seconds (5 minutes).
binding database changes. The range is from 15 to 86400 seconds. The
default is 300 seconds (5 minutes).
Step 5
end
Return to privileged EXEC mode.
Step 6
ip dhcp snooping binding mac-address
vlan vlan-id ip-address interface
interface-id expiry seconds
vlan vlan-id ip-address interface
interface-id expiry seconds
(Optional) Add binding entries to the DHCP snooping binding database.
The vlan-id range is from 1 to 4904. The seconds range is from 1 to
4294967295.
The vlan-id range is from 1 to 4904. The seconds range is from 1 to
4294967295.
Enter this command for each entry that you add.
Note
Use this command when you are testing or debugging the switch.
Step 7
show ip dhcp snooping database
[detail]
[detail]
Display the status and statistics of the DHCP snooping binding database
agent.
agent.
Step 8
copy running-config startup-config
(Optional) Save your entries in the configuration file.