> Bacause nginx smtp proxy is designed to protect / balance your own
> smtp backends. If you want to proxy to external smtp servers,
> consider using other solutions.

Thank you for answer!
1. what is the diff between "my smtp" and "3rd party smtp" from technical point of view?
2. which other solutions can you imagine? It's very interesting!
3. I've heared that "nginx mail module supports only non-ssl backeds". It's true?