Junos® OS For Dummies®, 2nd Edition

Configuring Junos OS Devices with the CLI

Remember, you can configure all devices running the Junos OS three ways: the console, the CLI interface, and J-Web. Note that because the SRX is a security device, it's a bit special. Even so, the initial configuration steps in this section apply to it, as well.

The Junos OS features two modes, configuration mode and operational mode — you configure the device with configuration mode and operate (monitor) its functions with operational mode (refer to Chapter 2 for more on this major division). Most configuration actions begin with set, and most operation commands begin with show. In the following sections, you first use configuration mode to configure the device and then you see how operation commands are used to watch the device perform.

All Junos OS devices come with almost the same bare-bones factory-default configuration when you turn them on. You use the same basic steps to complete the configuration, which we show you in the upcoming section, “Configuring the device.”

There are three copies (or images) of the software on Junos OS devices. One of these copies is on a CompactFlash card in the Routing Engine (see Chapter 3 for an overview of the Junos OS hardware). Another copy is on a rotating hard drive in the Routing Engine. The third copy is on a USB flash drive (on smaller devices such as the MX80) or a PC Card (on larger devices such as the T1600 core router) that can be inserted into a slot on the Routing Engine faceplate.

When ...