How can I remotely change router configurations to a totally new configuration file BUT have the ability to return to my original configurations without having someone at the sites. Currently have a network full of routers. We need to migrate these configuration to new configurations. My concept was to use the config Replace command to replace the current running config with a newly FTPed config residing in flash. Before that, I would have invoked the Reload command to reload the router if the newly replaced config had any problems as a backout plan. If everything came back up, I would log back on and Reload Cancel.

PROBLEM:

When I use the Config Replace command, I get errors unless the configuration is very simular as if the command only works if there is not radical changes in the configurations. One of the errors is "Error: Could not write to output buffer incremental-temp.cfg" another error would simply be that it was rolling back.

The configuration files that I Ftped were created by the IOS so they are in the correct config replace format.

Does anyone have any idea how I can do massive configuration changes on remote routers BUT have the ability to return to original configuration if needed without human intervention from the remote site?