Configuring Dhcp External Server To Uniquely Identify Clients With Duplicate; Mac Addresses - Juniper JUNOSE SOFTWARE 11.2.X - BROADBAND ACCESS CONFIGURATION GUIDE 7-20-2010 Configuration Manual

JunosE 11.2.x Broadband Access Configuration Guide
Configuring DHCP External Server to Uniquely Identify Clients with Duplicate MAC
Addresses
Related Topics
522
You can configure the DHCP external server application to use a combination of the MAC
address and giaddr to uniquely identify DHCP clients attached to the router. This behavior
is also referred to as duplicate MAC mode. By default, DHCP external server uses only the
MAC address to uniquely identify DHCP clients. The default behavior is also referred to
as unique MAC mode.
Enabling duplicate MAC mode is useful if you are using the DHCP external server
application to manage DHCP clients from multiple DHCP relays in network environments
where the same MAC address might be assigned to more than one client. In such
environments, DHCP external server must use a combination of the MAC address and
giaddr to uniquely identify the DHCP clients it manages.
Preserving the client's dynamic subscriber interface is useful if deleting and re-creating
the dynamic subscriber interface might result in a service interruption.
To configure the DHCP external server application to use a combination of the MAC
address and giaddr to uniquely identify DHCP clients, also known as enabling duplicate
MAC mode:
Issue the dhcp-external duplicate-mac-address command from Global Configuration
mode:
host1:vr1(config)#dhcp-external duplicate-mac-address
To restore the DHCP external server default behavior to use only the MAC address to
uniquely identify DHCP clients, also known as enabling unique MAC mode:
Issue the no dhcp-external duplicate-mac-address command from Global
Configuration mode:
host1:vr1(config)#no dhcp-external duplicate-mac-address
NOTE: Unlike other commands for configuring DHCP external server, the dhcp-external
duplicate-mac-address command applies globally to all instances of the DHCP external
server application on the router, and is not issued on a per-VR basis.
DHCP External Server Identification of Clients with Duplicate MAC Addresses Overview
on page 514
dhcp-external duplicate-mac-address
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