Connect Juniper Hardware to the Junos OS

Connect Juniper Hardware to the Junos OS

After you install the hardware, you’re ready to configure Junos OS beyond the factory default settings (which aren’t really appropriate for real-world situations). To do this, you have to connect to the Junos operating system running on the device.
In general, here are three ways to connect to Junos OS:

  • Via the console: All Junos OS devices have an RJ-45 console port called CONSOLE. You can connect from a laptop or other computer using a direct serial connector or through a console server. The console port does not require prior configuration, and there are no restrictions on what can be configured. Only a terminal emulator on a laptop or computer is required.


  • Via CLI interface: The RJ-45 console port is not the same as the CLI port used for TCP/IP remote access (often called ETHERNET). Physically, they look the same, but you must configure the IP address and mask for the CLI port before using it, usually through the serial console interface.

Once established, the dedicated management port (usually called fxp0) can be connected to an entire administrative LAN for management purposes, or through a router for universal access.

  • Via the J-web interface: J-web is not a separate port, but an interface that allows you to manage the Junos OS based on a graphical interface within a web browser. Although J-web is limited when it comes to debugging operations like traceoptions, J-web is a great way to quickly assess the overall health of a system (people interpret graphics much more quickly than they can read and understand words).

Each of the above three methods can be used to do almost any configuration task. However, most people use the console connection initially and then switch to the CLI or J-web for more detailed configurations, as we’ll see.
Although powerful, the method of configuring the console connection requires that a person be physically close to the device. The device could be placed on top of a mountain, in the middle of a remote desert, or locked in a locker in the block of cells in a maximum security prison.