Configuring the Router

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:
>enable
#configure terminal
(config)#hostname Router
Router(config)

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
Notes:

	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-if)#shutdown
Router(config)#router rip
Router(config-router)#network 10.0.0.0

Configuring RouterPassword Examples

Router(config)#line console 0
Router(config-line)#login
Router(config-line)#password cisco
Router(config)#line vty 0 4
Router(config-line)#login
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.
	Interface type and numbers must be defined when the interface command is used.
	Use the show interface command to verify configuration changes.