CCNA Commands|CISCO Router Configuration Command

CCNA Commands is very important knowledge for installing, configuring, operating and troubleshooting CISCO router.

CCNA (Cisco Certified Network Associate) is a certification from Cisco. CCNA certification is a first-level Cisco Career certification. CCNA certification  certify the capacity to install, configure, operate, and troubleshoot medium-size routed and switched networks, including implementation and verification of connections to remote sites in a WAN.

The following CCNA Commands is very essential for Cisco router configuration.

Mode		Definition
UserEXEC mode                                  Router>		Limited to basic monitoring commands
Privileged EXEC mode        Router#		Provides access to all other router com-mands
Global configuration mode      Router(config)#		Commands that affect the entire system
Specific configuration modes    Router(config-subif)#		Commands that affect interfaces,sub-interfaces, routing processes, or lines only

 Moving Between Modes:

Mode		Definition
Router>enable		Changes from user EXEC to privileged EXEC mode
Router#disable		Changes from user EXEC to privileged EXEC mode
Router#config		Term Changes to global configuration mode from privileged mode
Router(config)#exit		Exits from any configuration mode to privileged mode (Ctrl+Z is  also commonly used)
Router(config)#interface <int>		Enters interface configuration mode from global configuration  mode
Router(config)#interface <subint>		Enters subinterface configuration mode from global configuration mode
Router(config)#line <line>		Enters line configuration mode from global  configuration mode
Router(config)#router eigrp 1		Enters router configuration mode from global configuration mode

Mode		Definition
Ctrl+P or Up arrow		Shows last command entered
Ctrl+N or Down arrow		Shows previous commands entered |show history Shows last 10  commands entered by default| Shows terminal configurations and history buffer size terminal history size |Changes buffer size (the maximum is 256)
Ctrl+A		Moves your cursor to the beginning of the line
Ctrl+E		Moves your cursor to the end of the line
Esc+B		Moves back one word
Ctrl+B		Moves back one character
Ctrl+F		Moves forward one character
Ctrl+D		Deletes a single character
Backspace		Deletes a single character
Ctrl+R		Redisplays a line
Ctrl+U		Erases a line
Ctrl+W		Erases a word
Ctrl+Z		Ends configuration mode and returns to EXEC mode Tab Finishes typing a command for you
Tab		Finishes typing a command for you
Router#?		Shows all available commands
Router#c?		Shows all available commands beginning with the letter c
Router#clock ?		Shows all available options for the clock command

To set Date and Time

Router#clock set 16:45:00 12 jul 2011

Pipe Commands		Command Meaning
Router#sh running-config | ?		Shows the options for the pipe com-mand.  These include the  ability to begin, include, exclude, and so on.
Router#sh run | begin interface		Shows the running configuration, beginning at the interface configurations
Router#sh ip route | include 192.168.3.32		Shows all entries in the IP routing table that include the IP address  92.168.3.32.

Set Up  Host Name

Router(config)#hostname SpeedDatabase

Banners 

Command		Meaning
Router(config)#banner motd #		Enters a banner MOTD message and ends the message  with the # character
Router(config)#banner exec #		Enters a banner exec message and ends the message with the #  character
Router(config)#banner incoming #		Enters a banner incoming message and ends the mes-sage with the # character
Router(config)#banner login #		Enters a banner login message and ends the message with the # character

  

MOTD banner The MOTD banner will be displayed whenever anyone attaches to the

router, regardless of how they access the router.

Exec banner You can configure a line activation (exec) banner to be displayed when an

EXEC process (such as a line activation or incoming connection to a VTY line) is created. By

simply starting a user exec session through a console port, you’ll activate the exec banner.

Incoming banner You can configure a banner to be displayed on terminals connected to reverse

Telnet lines. This banner is useful for providing instructions to users who use reverse Telnet.

Login banner You can configure a login banner to be displayed on all connected terminals.

This banner is displayed after the MOTD banner but before the login prompts. The login

banner can’t be disabled on a per-line basis, so to globally disable it, you have to delete it with

the no banner login command.

  

Passwords

Setting Password		Command Meaning
Todd(config)#enable password todd		Sets the enable password to Todd
Todd(config)#enable secret todd		Sets the enable secret password to Todd. Supersedes the enable password.
Todd(config)#line		line Changes to line mode to configure the console, aux, and VTY (Telnet).
Todd(config-line)#password		password The line password for aux, console, and VTY   Telnet) are all set in line configuration mode
(When a line is configured to use a password, the login command must be set to prompt or login.)
Todd(config)#service  password-encryption		Encrypts the passwords in the clear-text configuration file (both running-config and startup-config).

Setting Password

Console

SpeedDatabase>en

SpeedDatabase#config t

SpeedDatabase(config)#line console ?

  <0-0>  First Line number

SpeedDatabase(config)#line console 0

SpeedDatabase(config-line)#password speed

SpeedDatabase(config-line)#login

SpeedDatabase(config-line)#exit

Telnet

SpeedDatabase(config)#line vty 0?

<0-15> 

SpeedDatabase(config)#line vty 0 15

SpeedDatabase(config-line)#password speed

SpeedDatabase(config-line)#login

SpeedDatabase(config-line)#exit

 Enable

SpeedDatabase(config)#enable password speed

Secret

SpeedDatabase(config)#enable secret database

Note: secrect password will  Supersedes the enable password

Password Encription

SpeedDatabase(config)#service password-encryption

Password Description

SpeedDatabase(config)#no service password-encryption

To save configuration

SpeedDatabase(config)#exit

SpeedDatabase#wr

Building configuration...

[OK]

Setting Exec Timeout

SpeedDatabase(config-line)#exec-timeout ?

  <0-35791>  Timeout in minutes

SpeedDatabase(config-line)#exec-timeout 0 ?

  <0-2147483>  Timeout in seconds

  <cr>

SpeedDatabase(config-line)#exec-timeout 0 100

SpeedDatabase(config-line)#exec-timeout 0 ?

  <0-2147483>  Timeout in seconds

  <cr>

SpeedDatabase(config-line)#exec-timeout 0 100

SpeedDatabase(config-line)#logging synchronous

Setting Up Secure Shell (SSH)

Instead of Telnet, you can use Secure Shell, which creates a more secure session than the Telnet

application that uses an unencrypted data stream. SSH uses encrypted keys to send data so that

your username and password are not sent in the clear. Table 1.9 lists the commands.

Command		Meaning
ip domain-name Lammle.com		Sets your domain name. You must set this.
crypto key generate rsa		Sets the size of the key up to 2048.
ip ssh authentication-retries		Sets the max failed attempts up to 120
line vty first-line last_line		Chooses your VTY lines to config

Tells the router to use SSH and then Telnet. You do not need the telnet command at the end of the line, but if you don’t use it, only SSH will work on the router.

Setting Up Secure Shell (SSH)

1. Set hostnameSpeedDatabase(config)#hostname speeddatabase

2. Set domain NameSpeedDatabase(config)#ip domain-name speeddatabase.com

3. Generate keysspeeddatabase(config)#crypto key generate rsa

The name for the keys will be: speeddatabase.speeddatabase.com

Choose the size of the key modulus in the range of 360 to 2048 for your

  General Purpose Keys. Choosing a key modulus greater than 512 may take

  a few minutes.

How many bits in the modulus [512]:2048

4. Set the maximam idle timer for an SSH sessionspeeddatabase(config)#ip ssh time-out ?

  <1-120>  SSH time-out interval (secs)
  speeddatabase(config)#ip ssh time-out 120

5. Set the maximum failed attemps for an SSH connectionspeeddatabase(config)#ip ssh authentication-retries ?

  <0-5>  Number of authentication retries

  speeddatabase(config)#ip ssh authentication-retries 3

6. Connect to VTY lines of the routerspeeddatabase(config)#line vty 0 15

7. Configure ssh and then tel net as access protocolsspeeddatabase(config-line)#transport input ssh
   speeddatabase(config-line)#transport input telnet

If you do not use the keyword telnet at the end of the command string, then only SSH will

work on the router. I suggest that you use just SSH if at all possible. Telnet is just too insecure

for today’s networks.