Juniper JUNOS Fundamentals

2. USER Interface

The JUNOS software provides a command-line interface (CLI) for managing and configuring the system, as well as a graphical user interface (GUI) for monitoring and troubleshooting network issues.

2.1 JUNOS CLI functionality

The JUNOS Command Line Interface (CLI) is a text-based interface for configuring, monitoring, and troubleshooting Juniper network devices running the JUNOS operating system. The JUNOS CLI provides a range of functionality that can be used to manage network devices, including:

1. Configuration: The JUNOS CLI provides a range of configuration commands that can be used to configure various aspects of the network device, such as interfaces, routing protocols, firewall filters, and other features.
2. Monitoring: The JUNOS CLI provides a range of monitoring commands that can be used to view the status and performance of the network device, such as the status of interfaces, the routing table, and other device components.
3. Troubleshooting: The JUNOS CLI provides a range of troubleshooting commands that can be used to diagnose and resolve network issues, such as debugging routing protocols, viewing system logs, and tracing packets.
4. Automation: The JUNOS CLI provides a scripting interface that can be used to automate repetitive tasks, such as configuring multiple devices with a single script, or generating reports on network performance.

The JUNOS CLI can be accessed from a local or remote terminal, or from a serial console connection to the device. The JUNOS CLI provides a comprehensive and flexible interface for managing and operating Juniper network devices.

Junos CLI modes

The JUNOS Command Line Interface (CLI) provides several modes that can be used to access different levels of functionality in the JUNOS operating system:

1. Operational mode: This mode provides access to information and commands related to the current state of the network device, such as viewing interface statistics, the routing table, and system logs. In operational mode, the prompt is ">" and the commands entered are not saved in the configuration.
2. Configuration mode: This mode provides access to commands for configuring the network device. In configuration mode, the prompt is "[edit]" and the commands entered are saved in the configuration. To enter configuration mode, use the "configure" command in operational mode.
3. Maintenance mode: This mode provides access to low-level commands and functionality, such as rebooting the device, restoring a configuration from backup, or recovering the root password. Maintenance mode can only be accessed from the serial console connection to the device.

To switch between modes, use the appropriate command in the current mode. For example, to switch from operational mode to configuration mode, use the "configure" command. To switch from configuration mode to operational mode, use the "commit and-quit" or "exit" command. To enter maintenance mode, follow the specific steps for your device and operating system.