But this does not restore to factory default state as the active running-config still exist. I was able to get to factory default state with "write erase or erase start and then reload". But this step involve rebooting the router. I am looking for default cli that allow me to restore to complete factory default without having to reload the router.

Thanks

Erase startup will wipe out the startup config . When you reload and it asks you if you want to save the config you say no and just reload .

Hello,

ok I see your issue now. Then the answer is: this option does not exist in IOS based systems. The only option would be to use "no" with all configured commands, but this is clearly not amusing in case you have a large config. If only one interface needs to be reverted to factory default, use "default interface ..." in config mode. Similar "default" commands exist for other parts of the config ("default ?" in config mode to check the options in your specific IOS).

So with IOS based systems the best practice procedure involves a reload after the steps described in the first posting.

Reason: There is no real equivalent to CatOS "clear config all" without reload.

Regards, Martin