[stunnel-users] How to distinguish stunnel definition between SMTP through SSL-TLS vs. STARTTLS?

Harris, Douglas (SSC/SPC) douglas.harris at canada.ca
Thu Oct 26 15:06:19 CEST 2017

> Ok, if I specify 
> protocol=smtp 
> what does that mean: "Connect through SSL-TLS protocol" or "connect through STARTTLS protocol"?

That means connect using STARTTLS.

> It seems to me that I ALWAYS have to specify "protocol=smtp" for ALL smtp-server connects.

You don't. If you are not using STARTTLS you don't specify "protocol=".

> Is this done only by port number 465 vs 587?


> That would mean there is a hidden configuration by convention!

Indeed. That would be bad.

> What if the webhoster would set up a special mail server at port 8888?

Then you would specify port 8888 in your "connect=" config

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