Configuring the Router
In preparation of our CCNA exam, we want to make sure we cover the various concepts that we could see on our Cisco CCNA exam. So to assist you, below we will discuss Configuring the Router.
From privileged EXEC mode, the configure terminal command provides access to global configuration mode. From global configuration mode, you can access specific configuration modes, such as the following:
  • Interface-Configures operations on a per-interface basis
  • Subinterface-Configures multiple virtual interfaces
  • Controller-Supports commands that configure controllers (such as E1 and T1)
  • Line-Configures the operation of a terminal line
  • Router-Configures IP routing protocols
    Assigning a Router Name Example
    The hostname command can name a router:
    #configure terminal
    (config)#hostname Router
    Configuring a Serial Interface Example
    Router#configure terminal
    Router(config)#interface s1
    Router(config-if)#clock rate 64000
    Router(config-if)#bandwidth 64
    Router#show interface serial 1
  • Unambiguous abbreviations of commands are allowed.
  • Abbreviations of delimiters are not allowed. For example, a clock rate of 64,000 cannot be abbreviated to 64.
  • The bandwidth command overrides the default bandwidth (1.544 Mbps). The bandwidth entered has no effect on the line’s actual speed.
    Major Command/Subcommand Relationship
    Commands that indicate a process or interface that will be configured are called major commands. Major commands cause the CLI to enter a specific configuration mode.
    Major commands have no effect unless they are immediately followed by a subcommand that supplies the configuration entry.
    Router(config)#interface serial 0
    Router(config)#router rip
    Configuring RouterPassword Examples
    Router(config)#line console 0
    Router(config-line)#password cisco
    Router(config)#line vty 0 4
    Router(config-line)#password ccna
    The numbers 0 to 4 in the line vty command specify the number of Telnet sessions allowedin the router. You can also set up a different password for each line by using the line vty port number command.
    Router(config)#enable password cisco
    Router(config)#enable secret kits
    Router(config)#service password-encryption
    The no enable command disables the privileged EXEC mode password.
    The no enable secret command disables the encrypted password.
    Note: When the enable secret password is set, it is used instead of the enable password.
    Configuring the Router Summary
  • Entering the configure terminal command from enable mode places you in global configuration mode. From this mode, you have access to the interface, subinterface, controller, line and router configuration modes.
  • You must save your running configuration to NVRAM with the copy running-config startup-config command. Failing to save your configuration to NVRAM causes your configurations to be lost if your router is reloaded.
  • Router security is achieved by password-protecting various access modes.
  • I hope you found this article to be of use and it helps you prepare for your Cisco CCNA certification. I am sure you will quickly find out that hands-on real world experience is the best way to cement the CCNA concepts in your head to help you pass your CCNA exam!
  • Interface type and numbers must be defined when the interface command is used.
  • Use the show interface command to verify configuration changes.