SSH needs to be re-enabled after tftp of modified configuration file to same router

[Ashley Gibbon]

I have been downloading files to TFTP server, modifying them (Not the SSH section) and TFTPing them back to the startup config. 

But when i reboot the router I need to regenerate the Keys for SSH to work with the following command.

crypto key generate rsa

768

Should I be able to do this without having to re-enable SSh and generate the keys?

Should I be managing he keys in a different way, It seems that some routers have keys in the configuration and some have them in NVRAM, does that sound possible?

[Richard Burts]

I wonder what kind of config changes you are making and whether that may have an impact on SSH. For example if you change the host name or change the domain name then the keys need to be regenerated.

HTH

Rick