| The majority of Cisco routers run Cisco IOS | | | | command exec modes in the IOS user interface. |
| Software with the command-line interface (CLI). | | | | Enable mode, also known as privileged mode or |
| The CLI is used to interface with the device and | | | | Privileged exec mode, and command mode are |
| send commands to the device. This is achieved | | | | the others. Enable mode is so named because the |
| through the use of a terminal, a terminal emulator, | | | | enable command is used to reach this mode. |
| or a Telnet connection. Some routing cards, such | | | | User mode allows commands that are not |
| as the Multilayer Switch Feature Card (MSFC) | | | | disruptive to be issued, with some information |
| daughter card for the Catalyst 6000 series LAN | | | | being displayed to the user. Privileged mode |
| switches, also run Cisco IOS Software. | | | | supports a superset of commands compared to |
| Understanding the Cisco IOS Software CLI is as | | | | user mode. However, none of the commands in |
| fundamental to supporting routers. There are | | | | user mode or privileged mode changes the |
| three ways in which you can access the CLI: you | | | | configuration of the router. Passwords are |
| access the router through the console; through a | | | | required for Telnet and auxiliary access as of |
| dialup device through a modem attached to the | | | | Cisco IOS Release 12.x and later. However, there |
| auxiliary port; or by using a Telnet connection. | | | | are no preconfigured passwords; therefore, you |
| Which ever method you use, you enter user | | | | must configure passwords for Telnet and auxiliary |
| exec mode first. User exec mode is one of three | | | | access from the console first. |