Router Configuration

Initialization step is used to configure the router is not too difficult. Cisco ios provides many tools that can be used to be added in the configuration file. It is expected that after passing through this module, you will be able to:

• Giving a name to the router
• Setting a password
• Understanding the show
• Set up the serial interface
• Set up the Ethernet interface
• Running the router changes
• Save configuration changes
• Configuring interface description
• Set up the message-of-the-day banner
• Set up the host table
• Understand how the importance of documentation and backup configuration file

1.Configuring the router
CLI command mode

All configuration will change the router CLI to global configuration or the global config. Config global configuration mode is most important. Global config used in the router to run the configuration commands. Prompt shown in the global config mode:

Router # configure terminal Router (config) #

Below are several modes that you can go to global config mode:

• Interface mode
• Line mode
• Router mode
• Subinterface mode
• Controller mode

Type exit from one of the above mode will return to global config mode. Emphasis Ctrl-Z will return to privileged EXEC mode.

Figure 1.1 modes in cisco router

Configuring the router
A router should have a unique name. Giving the name of the router is the first step router configuration.

Router (config) # hostname Tokyo
Tokyo (config) #

When Enter is pressed, the prompt changed from the default hostname to Tokyo.

Configuration password
Password should always configured for virtual terminal (vty) and the console terminal. Password is also useful to control access to privileged EXEC mode so that only certain people who can only make changes to router settings.
The command below is used to setup a password on the console terminal:

Router (config) # line console 0
Router (config-line) # login
Router (config-line) # password

Password must be set in one or more terminal vty Askes rights to the user who connect via telnet. Generally, the terminal has a cisco router vty 0 to 4. Some types may have different number of vty terminal. The following command to use for setting vty password in the terminal:

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

Commands enable password and enable secret is used to enter privileged EXEC mode. Enable password command is used only if
enable secret has not been set. Enable secret command should be used, because the enable secret password is encrypted. While the enable password is not encrypted. Below are the commands used to setup a password:

Router (config) # enable password
Router (config) # enable secret

Sometimes it is not very secure if the password in clear text on the display terminal from the console command show running-config or show startup-config. To avoid this use the command as follows:

Router (config) # service password-encryption

The above command will display an encrypted password. Enable secret command uses MD5 algorithm for encryption.

Figure 1.2 configuration on the router password

Show commands

• Show interfaces - to display all statistical router interface. To show a statistical interface, use the show interfaces command followed by the port number / slot interface such as the command below.

Router # show interfaces serial 0 / 1

• Show serial controllers - displays information specific hardware interface. This command must be set, including the port number / slot of the serial interface. Example:

Router # show controllers serial 0 / 1

• Show clock - shows the time settings in the router.
• Show hosts - the list manmapilkan cache of host name and address.
• Show users - manmpilkan all users who connect to the router.
• Show history - shows the history of commands that have been made.
• Show flash - display information about flash memory and ios files are stored there.
• Show version - displays information about the version of software that are now complete with the road information and hardware devices.
• Show ARP - ARP table shows the router.
• Show protocols - shows the status of the interface global and khusu of layer 3 protocols that terkonfigurasi.
• Show startup-config - displays the contents of the configuration file stored in NVRAM
• Show running-config - displays the contents of the configuration file or the current road configuration from the interface or map class information.

Configure serial interface
The steps to configure the serial interface is:

• Go to global configuration mode
• Log In interface mode
• Define the address of the interface and subnet masknya
• The clock rate when connected to the DCE cable. There is no need to clock rate setting if the cable is connected to the DTE
• Turn on the interface

Each serial interface must have an IP address and subnet mask for IP packet routing. Configuring IP address as follows:

Router(config)#interface serial 0/0
Router(config-if)#ip address

Serial interface requires a clock signal to control the timing of communication. DCE equipment in general such as CSU / DSU provides the clock. By default, the cisco router is a DTE equipment but is configured as DCE equipment.

In the serial link is connected directly, such as the configuration in the Lab, one side must be set as a DCE and must be set clocknya signal. For setting the clock speed and use the clock rate. Clock rate that is provided in bits per second is 1200, 2400, 9600, 19200.38400, 56000, 64000, 72000, 125000, 148000, 500000, 800000, 1000000, 1300000, 2000000, or 4000000. The setting depends on the capacity of the interface.

By default the interface is off or disabled. To enable menghidupkannya or using the command no shutdown. If you want to restore the situation more simply put off the shutdown.
In the lab, usually in the clock rate set to 56000. command used for setting the clock rate as follows:

Router(config)#interface serial 0/0
Router(config-if)#clock rate 56000
Router(config-if)#no shutdown

Figure 1.3 for the serial interface configuration

Make configuration changes
Before making changes, usually configurasi preview the current path with the command show running-config. If the variable is not displayed properly, to improve the way such as the following:

• Use no in front of the command
• Restore the configuration file from the beginning of the NVRAM
• Copy the configuration file from the TFTP server
• Remove the startup configuration file with the command erase startup-config, then restart and go to setup mode

To save the configuration file to the startup configuration in NVRAM, enter the privileged EXEC mode. As the command below.

Router#copy running-config startup-config

Figure 1.4 Procedure changes router configuration

Configure interface ethernet
Each interface must have the ethernet IP address and subnet mask for IP packet routing.
To configure the Ethernet interface as follows:

• Log in to the global config
• Go to the config interface
• Define interface address and subnet mask
• Enable interface

By default, the Ethernet interface in the off or disabled. To-kan-on with the command no shutdown. If you want to be returned off with the shutdown command.

Figure 1.5 configuration interface ethernet

2. Final configuration

Giving a description of the interface is very important to help users of information related to the interface, especially for large-scale network is very important to the provision of this description.
Description will also appear in the configuration file, although the description will not give any influence to the system.

Figure 2.1 a description of the interface

To configure the interface description, go to global config. Then log in to config by using the interface command such as the following description:

• Use the command configure terminal to enter global config
• Enter the interface to be configured, eg interface ethernet 0
• Enter a description, for example, XYZ Network, Building 18
• Use the keys Ctrl-Z to exit config interface and return to privileged EXEC mode
• Use the copy running-config startup-config to save the configuration changes to NVRAM

Here is an example interface description:
interface ethernet 0
description LAN Engineering, Bldg.2
interface serial 0
ABC network description 1, Circuit 1

Figure 2.2 of the interface description

Login banner
Is the message that appears at the time of login. Login banners can be used to convey the message to all users. For example a message "Welcome" as a welcome message for the user to login to the router.

Figure 2.3 example login banner

Configuring message-of-the-day (MOTD)
Go to global config to configure the MOTD banner. Use the banner motd command, followed by a space and the separator characters such as pound sign (#). As the example below:

• Use the command configure terminal to enter global config
• Enter the command banner motd # #
• Make the command copy running-config startup-config to save the changes

Figure 2.4 Configuration message-of-the-day (MOTD)

Host name resolution

Is the process where the computer system using the hostname with the IP address. To use the hostname IP communication with the other equipment, network equipment such as routers with IP diasosiasi must addressnya. Cisco ios memaintain cache mapping from name to address with the command EXEC. The speed of the cache affects the speed of conversion to the name address.
Hostname here is different from the DNS, where the hostname is just the name of the router.

Figure 2.5 hostname resolution

Hostname configuration table
To configure hostname table, first entry into the global config command ip host followed by the destination IP address. To perform testing connectivity to the host using the telnet or ping from the IP address followed by a goal. Procedure for configuring a host table as follows:

• Log in to the global config
• Enter the command ip host router followed by the name or IP address of the router dituju
• Repeat above steps until all the routers can be called
• Save configuration to NVRAM

Figure 2.6 host configuration table

Backup configuration files

Configuration should be saved and the backup for later in case there are problems with the system. Configuration can be stored on the server network (TFTP server) in the disk or stored in a secure place.

To save the current configuration the way to the TFTP server use the command copy running-config TFTP, such as the following steps

• Type the command copy running-config TFTP
• Enter the IP address of the TFTP server
• Enter the name of the configuration file
• Answer yes to confirmation

Configuration file stored on the network server can be used to configure the router. To do so as follows:

• Use the copy running-config TFTP
• Select the configuration file to include the router. Then enter the IP address the remote host where TFTP server is
• Enter the name of the configuration file or use the default name. Default name is hostname-config file for the host and network-config file for network configuration. Example file name: router.cfg

To save the configuration to disk, how to capture the text on the router and save.

Figure 2.7 the backup configuration