Cisco 4500M User Manual

33-6
Software Configuration Guide—Release 12.2(25)EW
OL-6696-01
Chapter 33 Configuring DHCP Snooping and IP Source Guard
Configuring DHCP Snooping on the Switch
Enabling the DHCP Snooping Database Agent
To configure the database agent, perform one or more of the following tasks:
Note Because both NVRAM and bootflash have limited storage capacity, using TFTP or network-based files
is preferrable. If you use bootflash to store the database file, new updates to the file (by the agent) result
in the creation of new files, causing the flash to fill very quickly. Moreover, when a file is stored in a
remote location accessible through TFTP, an RPR standby supervisor engine can take over the binding
list when a switchover occurs.
Note Network-based URLs (such as TFTP and FTP) require that you create an empty file at the configured
URL before the switch can write the set of bindings for the first time.
Configuration Examples for the Database Agent
The following examples show how to use the above commands.
Example 1: Enabling the Database Agent
The following example shows how to configure the DHCP snooping database agent to store the bindings
at a given location and to view the configuration and operating state:
Switch# configure terminal
Switch(config)# ip dhcp snooping database tftp://10.1.1.1/directory/file
Switch(config)# end
Switch# show ip dhcp snooping database detail
Agent URL : tftp://10.1.1.1/directory/file
Write delay Timer : 300 seconds
Abort Timer : 300 seconds
Command Purpose
Switch(config)# ip dhcp snooping database { url |
write-delay
seconds | timeout seconds }
Switch(config)# no ip dhcp snooping database
[write-delay | timeout]
(Required) Configures a URL for the database agent (or file)
and the related timeout values.
Switch# show ip dhcp snooping database [detail]
(Optional) Displays the current operating state of the
database agent and statistics associated with the transfers.
Switch# clear ip dhcp snooping database statistics
(Optional) Clears the statistics associated with the database
agent.
Switch# renew ip dhcp snooping database [validation
none] [
url ]
(Optional) Requests the read entries from a file at the given
URL.
Switch# ip dhcp snooping binding mac-addr vlan vlan
ipaddr interface ifname expiry lease-in-seconds
Switch# no ip dhcp snooping binding mac-addr vlan
vlan ipaddr interface ifname
(Optional) Adds/deletes bindings to the snooping database.

Cisco 4500M Specifications

General

Brand	Cisco
Model	4500M
Category	Network Router
Language	English