> On Jan 12, 2019, at 08:14, Viruthagiri Thirumavalavan <giri@dombox.org> wrote:

> My solution is intended for clients. A client should decide whether to transmit mails in clear text or not.

You should spend some time doing research by reading RFCs, and doing a little searching on the internet. Your proposal, would, canonically be called SMTPS.

If you put that into a search engine, you'll find not only is it deprecated, but has an assigned port number of 465.

https://en.wikipedia.org/wiki/SMTPS