When it comes to JunOS there are several operational modes that you must be familiar with. This lab will discuss and demonstrate the functionality of each user mode to help you better understand and navigate the JunOS CLI.
The JunOS shell is going to be familiar territory if you’ve ever worked with Unix and/or linux. This is because JunOS runs on FreeBSD. The only way you can access the Shell is if you log in using the root credentials in which case you’d be presented with the following;
vSRX_R1 (ttyd0) login: root Password: --- JUNOS 12.1X46-D10.2 built 2013-12-18 02:43:42 UTC root@vSRX_R1%
The Shell CLI is represented by “username@hostname%”. JunOS is the application that overlays FreeBSD to provide routing/switching functionality. Keep in mind that FreeBSD is open source, JunOS Software is not. The FreeBSD distro that JunOS is build on is a highly modified version of the kernel to support Juniper requirements.
The JNCIA does not require you to have an expert understanding of the BSD Shell but knowing your way around may be helpful.
Juniper maintains 49 past configuration revisions. The latest 3 revisions including the current config are stored in /config whereas older revisions that are archived are stored in /var/db/config
With that in mind the current running configuration is located at /config/juniper.conf.gz
Note that Juniper configuration is gziped to conserve space and ensure integrity. A native function of gzip is the integrity check which ensures that the contents of the gzip have not been modified or corrupted.