Configuring Dynamic Subscriber Interfaces For Interoperation With Dhcp Relay And Dhcp Relay Proxy - Juniper JUNOSE SOFTWARE 11.2.X - BROADBAND ACCESS CONFIGURATION GUIDE 7-20-2010 Configuration Manual

JunosE 11.2.x Broadband Access Configuration Guide
Configuring Dynamic Subscriber Interfaces for Interoperation with DHCP Relay and
DHCP Relay Proxy
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When you configure the DHCP relay application or the DHCP relay proxy application in
the same virtual router (VR) as the DHCP external server application, we recommend
that you define interface profiles to create the dynamic subscriber interfaces when the
primary IP interface is static. Otherwise, the gateway IP address (giaddr) used for DHCP
rebind or renewal requests might be inconsistent. Renewal requests apply only when
DHCP relay proxy is configured in the same VR as DHCP external server.
The use of inconsistent giaddrs results in the transmission of negative acknowledgment
(NAK) messages from the DHCP server and the removal of existing DHCP client bindings.
To apply an interface profile to a dynamic subscriber interface:
Define the interface profile.
1.
host1(config)#profile dsiTest
host1(config-profile)#ip unnumbered loopback 5500
host1(config-profile)#exit
Define a route map in the VR in which the static primary IP interface resides.
2.
host1(config)#virtual-router relay
Proceed with new virtual-router creation? [confirm]
host1:relay(config)#route-map dsiTest
host1:relay(config-route-map)#set ip interface-profile dsiTest
host1:relay(config-route-map)#exit
Define a loopback interface with a host mask in the VR in which the static primary
3.
IP interface resides.
host1:relay(config)#interface loopback 5500
host1:relay(config-if)#ip address 71.23.1.2/32
Enable the static primary IP interface to support creation of dynamic subscriber
4.
interfaces, and apply the route map to the IP interface subscriber in the static primary
IP interface configuration.
host1:relay(config)#interface fastEthernet 5/5.100
host1:relay(config-if)#ip unnumbered loopback 5500
host1:relay(config-if)#ip auto-configure ip-subscriber exclude-primary
host1:relay(config-if)#ip route-map ip-subscriber dsiTest
Use the exclude-primary keyword in the ip auto-configure ip-subscriber command
to specify that the primary interface cannot be assigned to a subscriber.
If you have issued the ip dhcp-external server-sync command to resynchronize the
5.
DHCP external server application with the router and to support creation of subscriber
state information based on lease renewals, you must do either of the following to
ensure that the unicast acknowledgment (ACK) response to the renewal request
has a route back to the DHCP client that generated the renewal request:
Enable the packet detection feature on the static primary IP interface in the context
of the VR in which the static primary interface resides.
Copyright © 2010, Juniper Networks, Inc.