Cisco IOS Command Line Interface Tutorial.pdf

Cisco IOS Command Line Interface Tutorial.pdf - Cisco IOS...

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Cisco IOS Command Line Interface Tutorial Abstract The focus of this document is to introduce a new Cisco Internetworking Operating System (IOS) user to the IOS command line interface (CLI). After reading this document, a new user will understand how to use the IOS CLI to configure and manage an IOS router. For easier reference, Table 1 displays a collection of important terms and acronyms that are used throughout the document. Table 1 - Glossary Of Important Terms And Acronyms Used In This Tutorial Cisco IOS - Cisco Internetworking Operating System CLI - Command Line Interface EXEC - Command line session to the router (could be console, modem, or telnet) Flash - Non-Volatile Memory used to store IOS software image NVRAM - Non-Volatile RAM used to store router configuration RAM - Random Access Memory CLI Architecture A Cisco IOS router command line interface can be accessed through either a console connection, modem connection, or a telnet session. Regardless of which connection method is used, access to the IOS command line interface is generally referred to as an EXEC session. As a security feature, Cisco IOS separates EXEC sessions into two different access levels - user EXEC level and privileged EXEC level. User EXEC level allows a person to access only a limited amount of basic monitoring commands. Privileged EXEC level allows a person to access all router commands (e.g. configuration and management) and can be password protected to allow only authorized users the ability to configure or maintain the router. For example, when an EXEC session is started, the router will display a "Router>" prompt. The right arrow (>) in the prompt indicates that the router is at the user EXEC level. The user EXEC level does not contain any commands that might control (e.g. reload or configure) the operation of the router. To list the commands available at the user EXEC level, type a question mark (?) at the Router> prompt. (This feature is referred to as context sensitive help .) Critical commands (e.g. configuration and management) require that the user be at the privileged EXEC level. To change to the privileged EXEC level, type "enable" at the Router> prompt. If an enable password is configured, the router will then prompt for that password. When the correct
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