Basic Configuration of Cisco Router

All CLI configuration will change the router to global configuration or global config. Config global configuration mode is most important. Global config is used in routers to execute configuration commands. The prompt shown in the global config mode:

Router # configure terminalRouter (config) # 

Below are a few modes that can go into global config mode:- Interface mode- Line mode- Router mode- Subinterface mode- Controller modeType exit from one of the above modes will return to global config mode. Emphasis Ctrl-Z will return to privileged EXEC mode.
Configuring a router name  
A router should have a unique name. Giving a name is the first step on the router configuration.Router (config) # hostname TokyoTokyo (config) #When pressed Enter, the prompt will change from the default hostname to Tokyo.

Configuration passwordPasswords should always be configured for virtual terminal (vty) and the console terminal. Password is also useful for controlling access to privileged EXEC mode so that only certain people are just biased change the router settings.The command below is used to setup a password on the console terminal:Router (config) # line console 0Router (config-line) # loginRouter (config-line) # password
Passwords should be set at one or more terminals to provide the right health insurance VTY users connect via telnet. Cisco routers generally have a terminal vty 0 through 4. Some other types may have different number of VTY terminals. The following commands are used for setting passwords on vty terminal:Router (config) # line vty 0 4Router (config-line) # loginRouter (config-line) # password
Commands enable password and enable secret is used to enter privileged EXEC mode. Enable password command is used only if it is because the enable secret password is encrypted. While the enable password is not encrypted. Below is the command used to setup a password:Router (config) # enable password
Router (config) # enable secret
Sometimes it is not safe if left in a state of clear text passwords on the console terminal screen from the command show running-config or show startup-config. To avoid this use a command like the following:Router (config) # service password-encryptionThe above command will give the appearance of the password is encrypted. Enable secret command uses MD5 algorithm for encryption.

These commands show- Show interfaces - to display the statistics of all router interfaces. To display the specific interface statistics, use the show interfaces command followed by the port number / slot interface such as the command below.Router # show interfaces serial 0 / 1- Show controllers serial - 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 - displays the time on the router.- Show hosts - manmapilkan cached list of host names and addresses.- Show users - manmpilkan all users who connect to the router.- Show history - shows history of commands that have been done.- Show flash - Displays information about flash memory and what IOS files are stored there.- Show version - displays information about the software version that is now under way complete with hardware and device information.- Show arp - Displays the ARP table of the router.- Show protocols - the interface displays the status of both global and khusu of layer 3 protocols are configured.- Show startup-config - displays the contents of the configuration file stored in NVRAM- Show running-config - displays the contents of the configuration file is the path or configuration of the interface or class map information. 

Configure serial interfaceThe steps to configure the serial interface is:- Go to global configuration mode- Sign in interface mode- Specifies an interface address and subnet masknya- Setting clock rate if a DCE cable connected. No need to clock rate settings if connected to the DTE cable- Turn on the interfaceEach serial interface must have an IP address and subnet mask for routing IP packets. Configuring the IP address as follows:Router (config) # interface serial 0 / 0Router (config-if) # ip address
Serial interfaces require a clock signal to control the timing of the communication. Generally DCE equipment such as CSU / DSU to clock it. By default, Cisco routers are DTE devices but the bias is configured as DCE equipment.On a serial link that is directly connected, 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 and speed by using the clock rate command. Clock rate provided in bits per second is 1200, 2400, 9600, 19200.38400, 56000th, 64000th, 72000th, 125000, 148000, 500000, 800000, 1 million, 1.3 million, 2 million, or 4 million. Setting depends on the capacity of the interface.By default the interface is in the off state or disabled. To enable it or enable it using the command no shutdown. If you want to restore to the state off again just entered the shutdown command.In the lab, the clock rate is usually set to 56 000. commands used for setting the clock rate as follows:
Router (config) # interface serial 0 / 0Router (config-if) # clock rate 56000Router (config-if) # no shutdown

Perform configuration changesBefore making changes, normally previewing configuration that is the way to the show running-config command. If the variable that is displayed is not correct, to fix the following way:- Use no in front of the command- Restore the initial configuration file from NVRAM- Copy the configuration file from the TFTP server- Remove the startup configuration file with the command erase startup-config, then restart and go into setup modeTo save the configuration to the startup configuration file in NVRAM, enter the privileged EXEC mode. As the command below.Router # copy running-config startup-config
Configure ethernet interfaceEach Ethernet interface must have an IP address and subnet mask for routing IP packets.To configure the Ethernet interface in the following way:- Go to the config global- Go to the config interface- Specify the interface address and subnet mask- Enable interfaceBy default, Ethernet interfaces in the off state or disabled. To on the command no shutdown. If you want to back off with the shutdown command.

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