Cisco common commands

A comprehensive list of Cisco common commands

To help you get through cisco certified better. What I want to share with you is the basic command of cisco certified. Welcome to read it!

several basic commands of the router:

Router> Enable enters privileged mode

Router#disable returns from privileged mode to user mode

router # configterminal enters global configuration mode

Router(config)# Interface ethernet 1 enters the Ethernet port with router number 1

exit and returns to the upper layer mode

end directly returns to the privileged mode

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = User configuration? File, the Default Settings file will be automatically loaded to initialize the switch to ensure the normal operation of the switch.

2. if CISCO Router is not found during initialization? User configuration? File, the system will automatically enter? Initialize configuration mode? (system configuration dialog mode, SETUP mode, STEP BY STEP CONFIG mode), it doesn't work normally!

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 1 This is usually used when you first start configuration.

2. AUX port (Auxiliary Management Interface): you can connect a MODEM to realize remote management and exclusive mode.

3. Telnet: Multi-person remote management (depending on performance and the number of VTY lines) is unsafe. Post-maintenance and remote management login.

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

Note. Pay special attention when modifying commands on running machines.

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　Router(config)#hostname ?

word this system's network name

in configuration mode, modify the local identifier of the current host. Example:

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router (config) # hostname r11

r11 (config) #

----<

A.B.C.D IP address

set the IP address for the current port, and enter the port to be configured before use. Example:

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r11 (config) # interface ethernet1

r11 (config-if) # ipaddress 172.16.1.1 255.255. < Show version

r11#show version to observe the IOS version, equipment working hours and related interface list

r11#show running-config to view the currently effective configuration. This configuration file is stored in ram

r11 # show interfaces ethernet1 to see the status of Ethernet interfaces. Working status, etc ...

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Show history view history command (recently used command)

r11 # terminalhistory size < -256> Set the size of the command buffer, : means not to cache

r11 # copyrunning-config startup-config to save the current configuration

Note concept:

nvram: non-volatile memory, and power-off information will not be lost <; -user configuration <; -RAM with startup-config

: random access memory, and all power-off information is lost <; -current effective configuration <; -save running-config

startup-config: every time a router or switch is started, Will actively load (default)

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = At the same time, it should end with a new line of [char c], describing the instructions when the machine logs in

r11(config-if)#description describes the interface comments. You need to

configure the password of the console port in the port configuration mode:

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R11 (config) # lineConsole enters CONSOLO

R11 (config-line) # PasswordEliuzd Set a password as? eliuzd?

r11(config-line)#login use password when setting login

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configure enable password:

------. Enable password cisco sets the enable password for plaintext

r11(config)# enable secret eliuzd sets the enable password for plaintext (used before plaintext)

r11 (config) # Service password-encryption system encrypts all plaintext passwords (weak function)

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Configure Telnet password:

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R11. line vty

　r11(config-line)#password cisco

　r11(config-line)# Login

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= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Virtual a port

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r11 (config) # interface loopback Create a loopback interface

r11 (config-if) # Ipaddress 192.168.1.1 255.255.255. configure its IP address

no * to reverse the configuration (delete the configuration).

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= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Show controllers serial is used to view the properties of DCE and DTE. The Router of serial router WAN port

DCE needs to configure the clock frequency

r11(config-if)#clock rate? Configure the clock frequency of DCE interface (system-specified frequency)

Generally speaking, this does not need to be configured by itself, because all DCE devices are in the operator's place.

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

The first line prompts that

serial 1 is administratively down and line protocol is down

the port

Serial1 is down was not activated with the no shutdown command. Line protocol is down

1. The other party has no shutdown activation port

2. The line is damaged, and the interface has no connection cable

Serial 1 is up, Line protocol is down

1. The other party has not configured the same Layer 2 protocol. Serial interface default encapsulation: HDLC

2. The clock frequency may not be configured

3. The three-layer address may not be configured correctly (possibly)

Serial1iUp. The line protocol is up

interface is working normally

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Show cdp neighbors to view CDP neighbors (excluding IP)

r11 # show CDP neighbors detail to view CDP neighbors (including three-layer IP addresses)

r11#show cdp entry * to view CDP neighbors (including three-layer IP addresses). The old command

r1(config)#no cdp run turns off the CDP protocol in global configuration mode (affecting all interfaces)

r1(config-if)#no cdp enable turns off the CDP protocol under the interface (only affecting the specified interface)

r11# Clear cdp table clear cdp neighbor table

r11#show cdp interface serial 1 view CDP information of the interface

note two tips:

sending CDP packets every 6 seconds.

HoldTime 18 seconds (each cdp packet is held for 18 seconds)

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Ip host sets a static host name mapping

r11#show sessions to view the mapped host names that have been set

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = You need to set the password of line vty, and configure the enable password if you need to enter the privileged mode

Example:

-----------------------router # telnet 192.168.1.1