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This feature module describes the Autoconfiguring Cisco IOS DHCP Server Options feature. This document includes the following sections:
The Dynamic Host Configuration Protocol (DHCP) server needed to be able to dynamically configure options such as the Domain Name System (DNS) and Windows Internet Name Service (WINS) addresses to respond to DHCP requests from local clients behind the customer premises equipment (CPE).
Previously, network administrators needed to manually configure the Cisco IOS DHCP server on each device enabled with this feature. After a router is deployed, it is labor-intensive, time consuming, and expensive to go to each location and make modifications.
Consequently, the Cisco IOS DHCP server was enhanced to allow configuration information to be updated automatically. Network administrators can configure one or more centralized DHCP servers to update specific DHCP options within the DHCP pools. The remote servers can request or "import" these option parameters from the centralized servers.
Dynamic configuration saves time and speeds the deployment of services to customers.
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
For descriptions of supported MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
None.
None.
This section documents new commands. All other commands used with this feature are documented in the Cisco IOS Release 12.1 command reference publications.
To import Dynamic Host Configuration Protocol (DHCP) option parameters into the DHCP server database, use the import all DHCP pool configuration command. To disable this feature, use the no form of this command.
import allSyntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
DHCP pool configuration
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
When the no import all command is used, the Cisco IOS DHCP server deletes all "imported" option parameters that were added to the specified pool in the server database. Manually configured DHCP option parameters override imported DHCP option parameters.
Examples
The following example allows the importing of all DHCP options for a pool named pool1:
ip dhcp pool pool1 network 172.16.0.0 /16 import all
Related Commands
ip dhcp database Configures a Cisco IOS DHCP server to save automatic bindings on a remote host called a database agent. show ip dhcp import Displays the option parameters that were imported into the DHCP server database.
Command
Description
To display the option parameters that were imported into the Dynamic Host Configuration Protocol (DHCP) server database, use the show ip dhcp import EXEC command.
show ip dhcp importSyntax Description
This command has no arguments or keywords.
Command Modes
EXEC
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
Imported option parameters are not part of the router configuration and are not saved in NVRAM. Thus, the show ip dhcp import command is necessary to display the imported option parameters.
Examples
The following is sample output from the show ip dhcp import command:
Router# show ip dhcp import Address Pool Name:2 Domain Name Server(s): 1.1.1.1 NetBIOS Name Server(s): 3.3.3.3
The following indicates the address pool name:
Address Pool Name:2
The following indicates the imported values, which are domain name and NetBIOS name information:
Domain Name Server(s): 1.1.1.1 NetBIOS Name Server(s): 3.3.3.3
Related Commands
import all Imports option parameters into the DHCP database. show ip dhcp database Displays Cisco IOS server database information.
Command
Description
Posted: Thu Sep 21 19:19:29 PDT 2000
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