Network Settings; Default Gateway; Backup Router; Loopback Address - Juniper J4350 Getting Started Manual

J4350 and J6350 Services Router Getting Started Guide
For Common Criteria compliance, you must configure NTP to provide accurate
timestamps for system log messages. For more information, see the Secure
Configuration Guide for Common Criteria and JUNOS-FIPS.

Network Settings

A Domain Name System (DNS) server on the network maintains a database for
resolving hostnames and IP addresses. Network devices can query the DNS server
by hostnames rather than IP addresses. The router accesses the DNS servers that are
added to the configuration to resolve hostnames in the order in which you list them.
If you plan to include your router in several domains, you can add these domains to
the configuration so that they are included in a DNS search. When DNS searches
are requested, the domain suffixes are appended to the hostnames.

Default Gateway

A default gateway is a static route that is used to direct packets addressed to
networks not explicitly listed in the routing table. If a packet arrives at the
Services Router with an address that the router does not have routing information
for, the router sends the packet to the default gateway. The default gateway
entry is always present in the routing and forwarding tables.

Backup Router

You can specify a backup router to take over when the routing protocol process
of the Services Router is not running, usually when the Services Router is
booting, or if its routing protocol process has failed. Packets arriving at a
Services Router in this situation are routed to the backup router. When the
routing protocol process starts up again, the address of the backup router is
removed from the routing and forwarding tables of the Services Router. The
backup router must be located on the same subnet.
NOTE: To configure a backup router, you must use the CLI or J-Web configuration
editor. You cannot configure a backup router with J-Web Quick Configuration.

Loopback Address

The loopback address is the IP address of the Services Router. The loopback
address ensures that the Services Router provides an IP address to management
applications. Because it must always be available to hosts attempting to route
packets to the Services Router, the loopback address resides on an interface that
is always active, known as the loopback interface (
address ensures that the Services Router can receive packets addressed to the
loopback address as long as the router is reachable though any entry (ingress)
interface. In addition, applications such as NTP, RADIUS, and TACACS+ can use
the loopback address as the source address for outgoing packets.
96
Basic Connectivity Overview
). Setting a loopback
lo0.0