Cisco Systems 78-11741-02 manual Eight IP addresses in one command line, IPC-74

Configuring DHCP

DHCP Configuration Task List

Configuring DHCP Server Options Import and Autoconfiguration

The Cisco IOS DHCP server can dynamically configure options such as the DNS and 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. 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. See the section “DHCP Server Options Import and Autoconfiguration Example” later in this chapter for a configuration example.

To configure the central router to update specific DHCP options within the DHCP pools, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1
	Router(config)# ip dhcp pool name	Creates a name for the a DHCP Server address pool and places you
		in DHCP pool configuration mode—identified by the
		(dhcp-config)# prompt.
Step 2
	Router(dhcp-config)# network	Specifies the subnet network number and mask of the DHCP
	network-number [mask /prefix-length]	address pool.
		The prefix length specifies the number of bits that comprise the
		address prefix. The prefix is an alternative way of specifying the
		network mask of the client. The prefix length must be preceded by
		a forward slash (/).
Step 3
	Router(dhcp-config)# dns-serveraddress	Specifies the IP address of a DNS server that is available to a DHCP
	[address2 ... address8]	client. One IP address is required; however, you can specify up to
		eight IP addresses in one command line.

To configure the remote router to import DHCP options into the DHCP server database, use the following commands beginning in global configuration mode:

	Command		Purpose
Step 1
	Router(config)# ip dhcp pool name		Creates a name for the a DHCP Server address pool and places you
			in DHCP pool configuration mode—identified by the
			(dhcp-config)# prompt.
Step 2
	Router(dhcp-config)# network		Specifies the subnet network number and mask of the DHCP
	network-number [mask /prefix-length]		address pool.
			The prefix length specifies the number of bits that comprise the
			address prefix. The prefix is an alternative way of specifying the
			network mask of the client. The prefix length must be preceded by
			a forward slash (/).
Step 3
	Router(dhcp-config)# import all		Import DHCP option parameters into the DHCP server database.
Step 4
	Router(dhcp-config)# exit		Exits DHCP pool configuration mode.
Step 5
	Router(config)# interface type number		Configures an interface and enters interface configuration mode.
Step 6
	Router(config-if)# ip address dhcp		Specifies that the interface acquires an IP address through DHCP.
	[client-id interface name] [hostname
	host-name]
		Cisco IOS IP Configuration Guide

IPC-74