# DHCP Local Server Prerequisites

Before you configure DHCP local server, you need to configure interfaces. You can configure ATM or Ethernet interfaces for DHCP local server. These interfaces can be numbered or unnumbered. Because subscribers connect to the router from different subnetworks, you must configure an IP address for each subnetwork on the interface. This action provides connectivity between the subnetwork and the router.

To configure a numbered IP address for DHCP local server:

1. Select an ATM or Ethernet interface.
2. Assign the primary IP address for one subnetwork to this interface.
3. Assign secondary IP addresses for all other subnetworks to this interface.

To configure an unnumbered IP address for DHCP local server:

1. Specify a loopback interface.
2. Assign the primary IP address for one subnet to the loopback interface.
3. Assign secondary IP addresses for all other subnets to the loopback interface.
4. Select an ATM or Ethernet interface.
5. Configure an unnumbered IP address associated with the loopback interface on the ATM or Ethernet interface.

For information about defining IP addresses, see the Configuring IP chapter in JunosE IP, IPv6, and IGP Configuration Guide.