What command is used to back up an IOS?

To back up an IOS, the command used is "copy flash tftp." This command takes the IOS image stored in the router's flash memory and copies it to a TFTP server, effectively creating a backup on that server.

The process involves specifying the source file (the IOS image) and the destination (the TFTP server's address), allowing network administrators to save a copy of the IOS for later use, such as recovery or for deploying on other devices. This is a crucial step in network management, as it ensures that there is a safe copy of the software that can be restored if necessary.

Using this method is advantageous because TFTP is a simple, lightweight file transfer protocol designed for situations where speed is more critical than security, making it effective for backing up files within trusted internal networks.

Other options do not accurately reflect the correct process for backing up an IOS image specifically to a TFTP server, demonstrating a fundamental understanding of the command structure required for this operation.