Backing up the running configuration

Use the write memory command to replace the startup configuration with the running configuration every time you make changes to the device configuration. To back up the device configuration to an external TFTP server, use the copy running-config tftp command.
device# copy running-config tftp 2001:DB8:e0ff:7837::3 newrun.cfg

This command example copies the running configuration to a TFTP server with the IPv6 address of 2001:DB8:e0ff:7837::3 and names the file on the TFTP server newrun.cfg.