Cisco IOS Commands

This is a master list of various Cisco IOS commands relevant to the CCNA track, along with brief descriptions of what each command does. Some commands may exceed CCNA requirements but provide valuable information.

Table of Contents

• Privileged Mode
• Set a Password for Console Access
• Set a Password for Virtual Terminal (Telnet) Access
• Set a Password for Auxiliary (Modem) Access
• Setting up the Router
• General Commands
• Processes and Statistics
• CDP Commands
• Miscellaneous Commands

Privileged Mode

Router>enable

Enters privileged mode.

Router#disable
Router>

Returns to user mode.

Router(config)#enable password knowing

Sets an unencrypted password for privileged mode.

Router(config)#enable secret knowing

Sets an encrypted password for privileged mode.

Set a Password for Console Access

Router(config)#line console 0
Router(config-line)#login
% Login disabled on line 0, until 'password' is set
Router(config-line)#password allknowing

Sets a password “allknowing” for console access.

Set a Password for Virtual Terminal (Telnet) Access

Router(config)#line vty 0 4
Router(config-line)#login
Router(config-line)#password knowingall

Sets a password “knowingall” for Telnet access.

Set a Password for Auxiliary (Modem) Access

Router(config)#line aux 0
Router(config-line)#login
Router(config-line)#password all

Sets a password “all” for auxiliary port access.

Setting up the Router

Router#show running-config

Displays the current running configuration from RAM.

Router#show startup-config

Displays the startup configuration from NVRAM.

Router#setup

Starts the initial configuration dialog.

Router#configure terminal

Enters global configuration mode.

General Commands

Router(config-if)#no shutdown

Enables the router interface.

Router#reload

Restarts the router.

Router#show version

Displays IOS version, uptime, and system information.

Processes and Statistics

Router#show processes

Displays active processes.

Router#show memory

Displays memory statistics.

CDP Commands

Router#show cdp neighbors

Shows directly connected neighbors using CDP.

Router(config-if)#no cdp enable

Disables CDP on a specific interface.

Router(config-if)#cdp enable

Enables CDP on a specific interface.

Miscellaneous Commands

R1#show controllers serial 0/1

Displays interface controller information.

R1(config-if)#clock rate 64000

Sets the clock rate on serial interfaces.

That’s the guide! For further details, consult the official Cisco documentation. Let me know if you’d like additional topics covered!

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