Cisco IOS 10 Basic Commands That Should Be Mastered

Posted on March 25, 2009 Updated on March 27, 2009

David Davis wrote in TechRepublic about the ten commands that a Cisco professional or network administrator should know when using the Cisco IOS in routers, switches, and firewalls. This is a good reminder for me, and I’m glad to know that I have embedded all of it in my brain already.

Below is the list he made plus my comments on what I think about each item.

1.    The “?”
This is the most helpful command ever. There are thousands of possible commands in the Cisco IOS and this is definitely useful when you don’t know or can’t remember the command to type, or the parameter that should come next.

2.    show running-configuration (sh run)
If you want to check the current configuration of the router, switch, or firewall, this is what is used.

3.    copy running-configuration startup-configuration (copy run start)
This command will save your current configuration, which is in the RAM, to the nonvolatile RAM (NVRAM). You can also use the copy command to copy to the TFTP server. If you must turn off your router, do not forget to use this command unless you don’t want to save the configuration changes you made.

4.    show interface (sh int)
For troubleshooting, this command is used to check the status of the router’s interfaces.

5.    show ip interface (sh ip int)
Much useful information about the configuration and status of the IP protocol and its services, on all interfaces are displayed with this command. Alternatively, you can add brief at the end of the command to get a shorter quick status.

6.    config terminal, enable, interface, and router (conf t, en, int, router)
These are used to enter different modes in configuring the router.

7.    no shutdown (no shut)
This is used to enable an interface, and also useful for troubleshooting when used with shut (to bring down interface then up).

8.    show ip route (sh ip ro)
To check the routing table, use this command.

9.    show version (sh ver)
This will display the router’s firmware settings, the last time the router was booted, the version of the IOS, the name of the IOS file, the model of the router, and the router’s amount of RAM and Flash.

10.    debug
This is helpful in troubleshooting. The debug command is used with other commands like for example, debug ip route.

Alright. That should be pretty simple to remember. Commands, stay in my brain please, thank you.

Photo Credit: dontthink.feel