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The Cisco command-line interface (CLI)
uses a hierarchical structure. This structure requires entry into
different modes to accomplish particular tasks. For example, to
configure a router interface, the user must enter interface
configuration mode. From interface configuration mode, all
configurations entered apply only to that particular interface. Each
configuration mode is indicated with a distinctive prompt and allows
only commands that are appropriate for that mode.
The IOS provides a command interpreter
service known as the command executive (EXEC). After each command is
entered, the EXEC validates and executes the command.
As a security feature the Cisco IOS
software separates the EXEC sessions into two access levels. These
levels are user EXEC mode and privileged EXEC mode. The privileged
EXEC mode is also known as enable mode. The following are the features
of the user EXEC mode and privileged EXEC mode:
- The user EXEC mode allows only a
limited number of basic monitoring commands. This is often referred
to as a “view only” mode. The user EXEC level does not allow any
commands that might change the configuration of the router. The user
EXEC mode can be identified by the “>" prompt.
- The privileged EXEC mode accesses
all router commands. This mode can be configured to require a
password from the user before accessing it. For added protection, it
can also be configured to require a user ID. This allows only authorized users to access
the router. Configuration and management commands require that the
network administrator be at the privileged EXEC level. Global
configuration mode and all other more specific configuration modes
can only be reached from the privileged EXEC mode. The privileged
EXEC mode can be identified by the "#" prompt.
To access the privileged EXEC level
from the user EXEC level, enter the
enable command at the “>”
prompt.  If
a password is configured, the router will then ask for that password.
For security reasons, a Cisco network device will not show the
password that is entered. When the correct password is entered, the
router prompt changes to “#”, indicating that the user is now at the
privileged EXEC level. Entering a question mark (?) at the
privileged EXEC level will reveal many more command options than those
available at the user EXEC level.
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Lab Activity
e-Lab Activity: Logging into the Router
This purpose of this lab is to access
the router command-line interface and activate privileged level
configuration options.
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Lab Activity
e-Lab Activity: Router User Interface Modes
In this lab, the students will learn to use the
enable command
to enter into privileged EXEC mode on the Cisco IOS.
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