Configuring Dhcp External Server To Uniquely Identify Clients With Duplicate Mac Addresses - Juniper JUNOSE SOFTWARE 11.0.X - BROADBAND ACCESS CONFIGURATION GUIDE 4-1-2010 Configuration Manual

JUNOSe 11.0.x Broadband Access Configuration Guide
Configuring DHCP External Server to Uniquely Identify Clients with Duplicate MAC
Addresses
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:
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:
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.
Related Topics
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Configuring DHCP External Server to Uniquely Identify Clients with Duplicate MAC Addresses

Issue the dhcp-external duplicate-mac-address command from Global
Configuration mode:
host1:vr1(config)#dhcp-external duplicate-mac-address
Issue the no dhcp-external duplicate-mac-address command from Global
Configuration mode:
host1:vr1(config)#no dhcp-external duplicate-mac-address
DHCP External Server Identification of Clients with Duplicate MAC Addresses
Overview on page 520
dhcp-external duplicate-mac-address