Cisco Router’s CLI Modes

The first thing a CCNA student must know is the CLI modes. These mode are structured in a hierarchical fashion, and each mode allows a group of specific commands. To access the CLI, you can use the console port or a remote access protocol such as Telnet or Secure Shell (CLI’s modes are part of the CCNA syllabus). Some of the CLI modes you’ve to familiarize with are described below:


User EXEC:

To access this mode you must log in the router by using the console port or a remote access technique (telnet, ssh…). At this mode, the prompt displays Router>, and you can telnet into a device, ping an IP address, displays the actual remote connections, Change terminal settings, and so on. But you cannot reload the router or configure anything because the privilege level is 1. To exit from the user EXEC mode issue the logout or exit command.

Privileged EXEC:

From user EXEC mode, issue the enable command to access the privileged EXEC. The enable statement is equivalent to enable 15 statement, and tells the router to enables the use of privileged commands. In this mode, the prompt displays Router#. The privileged mode allows you to troubleshoot and verify your configuration using the show and debug command. Additionally, this mode support a set of commands used to manage the router configuration files, backup/restore IOS image files, configure the router’s date and time, and reload the router. Issue the disable command or the exit command to exit from the privileged mode and return to user EXEC mode. If you’re in the configuration mode (global, interface, router…), you can go back to the privileged EXEC mode using the end command.

Global configuration:

To configure the router, you have to enter the global configuration mode. To do this, issue the configure terminal command from the privileged EXEC mode, and in this mode, the prompt displays Router(config)#. All the configurations are done in this mode, and if you wish to execute a privileged EXEC command such as the show command, you can precede it by the do command.

Interface configuration:

To configure an interface, you have to enter the interface’s configuration mode. To do this, issue the interface command from the global configuration mode or other configuration mode (line, router…), and in this mode, the prompt displays Router(config-if)#. If you wish to execute a privileged EXEC command such as the show command, you can precede it by the do command. You can go back to the privileged EXEC mode by pressing CTRL+Z. To exit from this mode, issue the exit command, and you’ll be moved to the global configuration mode.

Line configuration:

To configure access to the router using the console port or remotely, you have to enter the configuration mode of the specific line(s). To do this, issue the line command from the global configuration mode or other configuration mode (interface, router…), and in this mode, the prompt displays Router(config-line)#. If you wish to execute a privileged EXEC command such as the show command, you can precede it by the do command. You can go back to the privileged EXEC mode by pressing CTRL+Z. To exit from this mode, issue the exit command, and you’ll be moved to the global configuration mode.

Router configuration:

To configure a router protocol, you have to enter the configuration mode of a specific routing protocol. To do this, issue the router command from the global configuration mode or other configuration mode (line, interface…), and in this mode, the prompt displays Router(config-router)#. If you wish to execute a privileged EXEC command such as the show command, you can precede it by the do command. You can go back to the privileged EXEC mode by pressing CTRL+Z. To exit from this mode, issue the exit command, and you’ll be moved to the global configuration mode.