CISCO IOS in a Nutshell

IOS User Modes

There are two primary modes of operation within the IOS: user mode and privileged mode. When you first connect to the router, you are placed in the user mode. The Cisco documentation refers to this as the user exec mode; I am going to omit “exec” throughout this book. The user mode is indicated by the prompt:

Router>

Tip

The word “Router” is replaced with your router’s hostname if the hostname is already configured.

The show commands in user mode are limited to a few basic levels. You cannot edit or view configurations at this stage; you can only view the router status and other miscellaneous information. To obtain a basic listing of commands, type a question mark:

Router>?

Editing the router’s configuration requires you to be in the privileged exec mode, which I simply call “privileged mode.” Use the enable command to enter this mode:

Router>enable
Password:
Router#         Privileged mode prompt

You can always tell whether you are in user mode or privileged mode by looking at the prompt. The user mode prompt has a > at the end; the privileged mode prompt always has a # at the end, regardless of the submode.

If you are familiar with Unix, you can equate privileged mode to “root” access. You could also equate it to the administrator level in NT or the supervisor in NetWare. In this mode, you have permission to access everything inside the router, including configuration commands. However, you can’t type configuration commands directly. Before you can change the router’s actual ...