Juniper NetScreen 5GT Wireless, User Manual

Chapter 2 Configuring the Device

28

User’s Guide

Configuring a Backup Untrust Zone Interface

By default, on NetScreen-5GT Wireless ADSL device, the adsl1 interface is the primary 
connection to an outside network. Each port mode available on the NetScreen-5GT 
Wireless ADSL device allows you the option of connecting either the Untrusted Ethernet 
port or the Modem port as a backup connection to the outside network (see 

“Changing the 

Port Mode” on page 26

). You must bind the backup interface to the Untrust zone and 

configure the interface appropriately.

For example, to bind the Untrust interface to the Untrust zone:

WebUI

Network > Interfaces > Edit (for the untrust interface): Select Untrust from the 
Zone Name drop-down list, and then click OK.

CLI

set interface untrust zone untrust

save

You also need to set a static IP address for the Untrust interface, or specify whether the 
IP address for the interface is obtained via either DHCP or PPPoE. See the “Interfaces” 
chapter in the “Fundamentals” volume of the NetScreen Concepts & Examples ScreenOS 
Reference Guide for ScreenOS 5.0.0 for more information about configuring interface 
parameters.

When the adsl1 interface and either the Ethernet interface (named untrust or ethernet3, 
depending upon the port mode) or the serial interface is bound to the Untrust zone, 
interface failover is automatically configured. That is, if the adsl1 interface becomes 
unavailable, the NetScreen device automatically sends traffic to the backup interface. The 
device automatically sends traffic to the adsl1 interface when the adsl1 interface is again 
available.

You can also manually force failover and failback on the adsl1 interface. For more 
information, see the “Interface Redundancy” chapter in the “High Availability” volume of 
the NetScreen Concepts & Examples ScreenOS Reference Guide for ScreenOS 5.0.0.

Note: You can configure only one backup interface, using either the Untrusted Ethernet 
port or Modem port connection. If you use the Untrusted port for the backup connection, 
then configure the Untrust interface in Trust-Untrust port mode or the ethernet3 interface 
for other port modes. If you use the Modem port for the backup connection, then configure 
the serial interface for all port modes.

Note: Only the adsl1 interface is affected by failover. That is, if you have also configured 
ADSL subinterfaces, the subinterfaces do not fail over to the backup interface.