start junos

Juniper Networks routers are specialized network devices that run network operating system software, which is called JUNOS software. We talk about JUNOS features that run on the J-series, M-series, and T-series router platforms. The M-series and T-series platforms are larger routers typically used by network service providers, telephone companies, large enterprise companies, and universities. The J-series routers are smaller routers designed for use by businesses and other organizations to connect multiple sites or to connect to the Internet. The JUNOS software is pre-installed on a new Juniper Networks routers: when you turn the router on, the software automatically starts running. The first task you have to perform is configuring the router.
for example

 root# cli
 root@>
 cli> configure
 [edit]
 root@# set system host-name router1
 root@# set system domain-name mynetwork.com
 root@# set interfaces fxp0 unit 0 family inet address 192.168.15.1/24
 root@# set system backup-router 192.168.15.2
 root@# set system name-server 192.168.15.3
 root@# set system root-authentication plain-text-password
 New password:
 Retype password:
 root@ show
 system {
     host-name router1 
;
     domain-name mynetwork.com;
     backup-router 192.168.15.2;
     root-authentication {
          encrypted-password "$1$ZUlES4dp$OUwWo1g7cLoV/aMWpHUnC/"; ## SECRET-DATA;
     }
     name-server {
          192.168.15.3;
 }
 interfaces {
     fxp0 {
         unit 0 {
             family inet {
                 address 192.168.15.1/24;
             }
         }
     }
 }
 root@# commit
 root@router1# exit
 root@router1>

While the configuration shown in this recipe provides the minimum needed to access the router from another system on the network, you should add a few other settings to the configuration to provide a more robust level of basic network connectivity:

 [edit]
 root@router1#  
set system ntp server 192.168.2.100
 root@router1# set system time-zone America/Los_Angeles
 root@router1#  
set system services ssh
 root@router1# set interfaces lo0 unit 0 family inet address 207.17.139.42/32
 root@router1# set system login user aviva class superuser
 root@router1# set system log user aviva authentication plain-text-password
 New password:
 Retype new password:
 root@router1# commit

 P address of the router's fxp0 interface, with the set interfaces fxp0 command. fxp0 is an Ethernet management interface that provides a separate out-of-band management network on the router. (The J-series routers do not have a dedicated management interface. You use one of the built-in Fast Ethernet interfaces, fe-0/0/0 or fe-0/0/1, instead.) Juniper Networks recommends that you manage all M-series and T-series routers using the fxp0 interface, which is reserved for managing the router, so no traffic is forwarded through it. As part of the physical setup for the router, you should connect fxp0 to an Ethernet network over which you can perform management tasks. Optimally, the router should also be able to reach its DNS and NTP servers through this network. If you prefer, you can use any other interface router as a management interface. For the remainder of this book, we assume that fxp0 (or fe-0/0/0 on J-series routers) is configured as the management interface.
IP address of a backup router, with the set system backup-router command. Choose a router that is directly connected to the local router. Your router uses this backup router only when it is booting and only if the JUNOS routing software (called the routing protocol process, or RPD) does not start. If RPD does not start, the router will have no static or default routes, so you will not be able to access it directly but will have to go through the backup router. When the router is booting, it creates a static route to the backup router. This route is removed from the routing table as soon as the routing software starts.
For routers with two Routing Engines, the backup Routing Engine, RE1, still uses the backup router as a default gateway after the router has booted, so you can use the backup router to log in to RE1.(RE0 is the primary, or master, Routing Engine.see next post configuring back-router