Familiarizing CISCO IOS

Lab Objectives

• Familiarize yourself with the different modes on a Cisco IOS based Device.
• Familiarize yourself with legacy terminal keystroke combination’s for CLI navigation.

Lab Instruction

Mastering the navigation through the Cisco command line interface is an absolute requirement for any Cisco engineer. There are several different types of modes in the Cisco CLI. User mode is the mode you’re first placed into upon pressing return after entering your user authentication information, vty or line password. Once you’re placed into User Mode, you’re limited as to the commands you’re able to execute from the CLI.

However, many commands at the user level can be very informative such including but not limited to; ping,traceroute, show cdp neighbors, show version and show interface command(s).

In privileged mode, you’re given the ability to configure the device and execute management commands including but not limited to; configure, clear, reload, more, copy, delete, erase and debug.

As shown below in the terminal box you can see that after pressing return you’re placed into Cisco CLI with the “>” greater then sign next to the hostname. This is called user mode.

Router con0 is now available Press RETURN to get started. Router>

At any point in the Cisco CLI you can use the question mark to get a context mode sensitive help list of available commands to execute from your current privilege level. shown below;

Router>? Exec commands: access-enable Create a temporary Access-List entry access-profile Apply user-profile to interface clear Reset functions connect Open a terminal connection crypto Encryption related commands. disable Turn off privileged commands disconnect Disconnect an existing network connection emm Run a configured Menu System enable Turn on privileged commands ethernet Ethernet parameters exit Exit from the EXEC help Description of the interactive help system lat Open a lat connection lock Lock the terminal login Log in as a particular user logout Exit from the EXEC mrinfo Request neighbor and version information from a multicast router mstat Show statistics after multiple multicast traceroutes mtrace Trace reverse multicast path from destination to source name-connection Name an existing network connection --More--

You can use return to show line by line or space bar to show the next paragraph of available commands. If you wish to exit the list without pressing space bar continuously to reach the end of the list, press the Qkey.

When in user mode you can elevate your privileges by issuing the command enable from the user mode cli prompt. If you have an enable password or enable secret configured then you’ll be prompted to provide such authentication information to elevate your privileges.

NOTE: When entering the password information via CLI, you will NOT see the characters you’ve typed.

Router>enable Password: Router#

Once in privileged mode you’re able to execute commands that allow you to maintain and configure the device such as copy running-configuration startup-configuration

Router#copy running-config startup-config Destination filename [startup-config]? Building configuration... [OK] Router#

When you’re in privileged mode you can configure the router by entering the command configure terminal. This command will place you into global configuration mode where you can make device configuration changes. Note that this may not always be the case, if a Cisco Access Control Server is used for command authorization then each command you execute will be authorized by the Cisco ACS server prior to execution. The ACS Server (which is outside of the scope of the CCNA Certification) allows security engineers to control which users can execute which commands based on configured policies.

Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#

Within global configuration mode (denoted by the (config)# prompt) you have access to different configuration modes such as interface configuration mode, router configuration mode, VLAN Database configuration mode, access-list configuration mode and many others;

Router(config)#interface f0/0 Router(config-if)#router eigrp 1 Router(config-router)#ip access-list extended example_acl_name Router(config-ext-nacl)#line con 0 Router(config-line)#

To exit a specific mode to the previous mode just execute the command exit

In the early days of the Cisco IOS, keystroke navigation was used. Now days this type of navigation is considered “legacy” and no longer used but there is that .001% change that one day you’ll need it so its good to be aware of its existence.

Key	Result
ESC + F	Move insertion point to the beginning of the next word.
ESC + B	Move insertion point to the beginning of the current word.
ESC + DEL	Erase previous word.
ESC + D	Erase word, or section of a word, following the insertion point.
ESC + C	Capitalize letter following the insertion point.
ESC + U	Change next word or word section to all UPPERCASE letters.
ESC + L	Change next word or word section to all lowercase letters.
CTRL + A	Move insertion point to the beginning of the line.
CTRL + E	Move insertion point to the end of the line.
CTRL +	Erase entire command line you’re working on (to the insertion point’s left).
CTRL + T	Transpose previous two characters.
CTRL + K	Erase from the cursor to the start of the command line.
CTRL + R	Search the list of commands incrementally based on what you type.
Tab	Complete the path or filename.
UP Arrow	List previous commands up.
DOWN Arrow	List previous commands down.