Juniper ACX2000 Configuration Guide

Release History Table DescriptionRelease
Starting with Junos OS Release 15.1X49-D10, the special loopback interface
is no longer supported on SRX300, SRX320, SRX340, SRX345, and
SRX550HM devices. Refer Special Interfaces for more details on special
loopback interface.
15.1X49-D10
Related
Documentation
Configuring a Loopback Interface•
• Understanding Interfaces
• Understanding Management Interfaces
• Understanding the Discard Interface
Configuring the Loopback Interface
•
Configuring the Loopback Interface on page 101
•
Example: Configuring Two Addresses on the Loopback Interface with Host
Routes on page 102
•
Example: Configuring Two Addresses on the Loopback Interface with Subnetwork
Routes on page 103
•
Example: Configuring an IPv4 and an IPv6 Address on the Loopback Interface with
Subnetwork Routes on page 103
Configuring the Loopback Interface
When specifying the loopback address, do not include a destination prefix. Also, in most
cases, do not specify a loopback address on any unit other than unit 0.
NOTE: For Layer 3 virtual private networks (VPNs), you can configure multiple
logical units for the loopback interface. This allows you to configure a logical
loopback interface for each virtual routing and forwarding (VRF) routing
instance. For more information, see the Junos OS VPNs Library for Routing
Devices.
For some applications, such as SSL for Junos XML protocol, the address for
the interface lo0.0 must be 127.0.0.1.
You can configure loopback interfaces using a subnetwork address for both inet and
inet6 address families. Many protocols require a subnetwork address as their source
address. Configuring a subnetwork loopback address as a donor interface enables these
protocols to run on unnumbered interfaces.
If you configure the loopback interface, it is automatically used for unnumbered interfaces.
If you do not configure the loopback interface, the router chooses the first interface to
come online as the default. If you configure more than one address on the loopback
101Copyright © 2017, Juniper Networks, Inc.
Chapter 4: Configuring Interfaces and Chassis

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English