Cisco Router Configuration Files, startup-config, running-config, Start-up Configuration file, Running Configuration file

Cisco Router configuration files hold the commands to configure the router. There are two main copies of Cisco Router configuration file. The configuration file where router stores the configuration changes when the router is up and running is called the "running-config" file. The running configuration file stores the configuration changes made while the router is up and running. The "running-config" file is stored in RAM. The "running-config" file is NOT persistent, which means that the changes made in the "running-config" while the router is running are not retained after a reboot. You can back up, or save, "running-config" file to either NVRAM or a TFTP (Trivial File Transfer Protocol) server.

A persistent copy of Cisco Router configuration file is called as "startup-config" file. The "startup-config" file is kept in NVRAM and the contents of the "startup-config" file are retained after a reboot. To save the changes of "running-config" file to "startup-config", run the following IOS command.

OmniSecu03# copy running-config startup-config 

The "running-config" can also be saved in a TFTP (Trivial File Transfer Protocol) server if you have a TFTP (Trivial File Transfer Protocol) server in your network. To save "running-config" file to a TFTP (Trivial File Transfer Protocol) server, run the following IOS command.

OmniSecu03# copy running-config tftp 

Remember, "startup-config" is a persistent copy of configuration file, which is kept normally in NVRAM.