Backing up system images and configurations on Cisco routers is essential, as it guarantees recovery from hardware failures, software problems, or unintentional changes. Backups allow you to quickly restore working settings and software versions, which reduces downtime and aids in troubleshooting. This practice ensures network security, uniformity, and regulatory compliance, saves time, reduces costs, and ensures reliable network operations.
To backup an image or configuration file, you need to use the “copy” command and define the source and destination parameters (“copy source destination”). For example, if you want to upload the software image on the router to a TFTP server (and maybe use it later on another router), you must use the “copy flash ftp” command.
This command initiates a wizard where you need to specify the source image file name, the TFTP server’s IP address, and the destination file name. To find out the name of the local image file, you must use the “show flash” command.
In addition, you can also use the same “copy” command to back up the running or startup configurations on the router to the local flash or external TFTP server. The configuration example below shows how you can copy the router running configuration to a TFTP server.
However, you should be careful when copying configurations. Typically, the source file rewrites the destination file if they use the same names. For example, copying the running-config.cfg file (running configuration) of the router to an external TFTP server, where the same filename already exists.
While this is the default behavior, there is an exception to this rule. When you copy the configuration file from any location into RAM (running-config), instead of overwriting the running configuration, both configurations merge.
As you can see in the image above, anytime you copy a configuration file into RAM, it merges with the current running configuration instead of overwriting it. The example below provides the result of copying a configuration on a TFTP server into the running configuration on a router:
The following configuration example shows how you can copy (merge) a configuration file on a TFTP server into the running configuration on a router:
