Booting and the basic configurations of the Cisco Router

We had discussed the router and its components in the previous article. Today we are going to configure the Cisco Router. In this post, I will cover just only the basic configurations that commonly used in a fresh router.

Connecting to Computer

Router for the first time is configured through the CONSOLE port. COM port of a PC is connected to the console port of router with a console cable by using a transceiver. The router is accessible by a tool. In windows, it is called HYPER TERMINAL. (W can use ‘telnet’ tool for the same operation).

Powering on

A Router initializes by loading the bootstrap, the operating system, and a configuration file.  If the router cannot find a configuration file, it enters setup mode.

Upon completion of the setup mode, a backup copy of the configuration file may be saved to non-volatile RAM (NVRAM).

Routine startup of the Router

Make sure that the router hardware is tested and functional.

Find and load the Cisco IOS software.

Find and apply the startup configuration file or enter the setup mode

Power-On-Self-Test (POST)

When a Cisco Router powers up, it performs a power-on-self-test (POST). During this self-test, the router executes diagnostics from ROM on all hardware modules.

After the POST, the following events occur as the router initializes: 

Step 1

The generic bootstrap loader in ROM executes. Bootstrap is a simple set of instructions that tests hardware and initializes the IOS for operation. 

Step 2

The IOS can be found in several places. The boot field of the configuration register determines the location to be used in loading the IOS. If the boot field indicates a flash or network load, boot system commands in the configuration file indicate the exact name and location of the image.

Step 3

The operating system image is loaded.

Step 4

The configuration file saved in NVRAM is loaded into main memory and executed one line at a time. The configuration commands start routing processes, supply addresses for interfaces, and define other operating characteristics of the router.

Step 5

If no valid configuration file exists in NVRAM, the operating system searches for an available TFTP server. If no TFTP server is found, the setup dialogue is initiated...

In the Setup Mode, We will get one message like below

“Would You Like To Enter The Initial Configuration [Y/N]:”

If “Y” then, Initial Configuration starts.

If “N” Would you like to terminate the auto-installation? Press “RETURN” to get started.

We will get the default router prompt like “Router>”

Router Working Modes

The Cisco Router has many modes and each mode is used for configuring different features like Routing, DHCP, VPN, etc.

User Mode (Default mode) - Router>

Router mode is the default prompt. Whenever a router boots successfully it lands into the user mode. The router cannot be configured from this mode, but it is used for just monitoring purposes.

Privilege Mode (Administrative) - Router#

Use the enable command in Router> mode for activating privilege mode

(Router>en, Router#)

‘Router#’ in this mode we can check whether the settings and configurations made have been implemented or not. E.g. Router # S hint s0/0.

Global Configuration Mode – RouterConfig)#

Configure terminal command is used for entering the Global Configuration Mode.

Router # config t

Router(config)#

This mode is used to configure the router interfaces. Most of the configurations start from Global Configuration Mode.

Interface Configuration Mode – Router(config-if)#

For enabling the interface mode, we can use the command ‘interface interface name’ from the router config mode.

Router(config)#int f0/0

Router(config-if)#

Interface configuration mode allows configuring the router interfaces for different routing and monitoring functions.

Basic Configurations of the Router

The Router configuration is starting from the default prompt mode of the router, Router>.

Router Name (Command ‘hostname’)

We can use a unique name for the router. This will help us to identify the router easily.

Router>en

Router#config t

Router(config)# hostname thewantricks

thewantricks(config)#       (Router name changed to ‘thewantricks’)

Time and Date

‘clock’ command is used for setting up the time and date on the router. This configuration is done from privilege mode.

thewantricks#clock set hh:mm:ss: day of week month year

thewantricks#clock set 12:41:35 1 September 2017

Message of the Day (MOTD)

This will help to show the welcome messages on all connected terminals. The Administrator can also create legal warnings using this MOTD.

thewantricks(config)#banner motd # Welcome Authorized Users Unauthorized access prohibited!#

Password Configuration

Privilege Password – Enable and Secret Password

It is a global command restrict access to the privilege mode. Enable password is in the clear text format and Secret password is in an encrypted format.

Enable Password Configuration

thewantricks(config)#enable password 2532

Secret Password Configuration

thewantricks(config)#enable secret ciscounique

Virtual Terminal Password

It enable login password for incoming telnet secessions.

thewantricks(config)#line vty 0 4

thewantricks(config-line)#login

thewantricks(config-line)#password cisco

thewantricks(config-line)#^Z

Console Password

It establishes a login password on the console terminal.

thewantricks#conf t

thewantricks(config)#line console 0

thewantricks(config-line)#login

thewantrciks(config-line)#password cisco

thewantricks(config-line)#^Z

Auxiliary Password

It establishes a login password to remote administration.

thewantricks#conf t

thewantricks(config)#line Aux 0

thewantricks(config-line)#login

thewantricks(config-line)#password cisco

thewantricks(config-line)#^Z

Topic Conclusion

This article explains the basic configuration of the Cisco Router. The other routing operations and important commands will explain on the next topic.