Enabling The Dhcp Snooping Database Agent; Configuration Examples For The Database Agent - Cisco 4500M Software Manual

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:
Command
Switch(config)# ip dhcp snooping database { url |
write-delay seconds | timeout seconds }
Switch(config)# no ip dhcp snooping database
[write-delay | timeout]
Switch# show ip dhcp snooping database [detail]
Switch# clear ip dhcp snooping database statistics
Switch# renew ip dhcp snooping database [validation
none] [ 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
Because both NVRAM and bootflash have limited storage capacity, using TFTP or network-based files
Note
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
Software Configuration Guide—Release 12.2(25)EW
33-6
Chapter 33 Configuring DHCP Snooping and IP Source Guard
Purpose
(Required) Configures a URL for the database agent (or file)
and the related timeout values.
(Optional) Displays the current operating state of the
database agent and statistics associated with the transfers.
(Optional) Clears the statistics associated with the database
agent.
(Optional) Requests the read entries from a file at the given
URL.
(Optional) Adds/deletes bindings to the snooping database.
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