I setup a secure mail relay partly using a sample setup published at this forum (the one using stunnel).
Since I already had a working https server using stunnel, I think the smtps server is setup correctly (I did not have to do anything more than starting a new stunnel daemon with new port specifications, and redirect port 465 to the internet gateway's same port, like I do with POP3s and https).

However, I cannot find a mail client on my home machine which would be able to use it:
- Opera 7.04 did not even accept my personal certificate (unlike netscape and konqueror)
- Netscape 6 always connects to port 25, even when the "use SSL" box is checked
- kmail seems to have no smtps option
Since I use SuSe 7.3, I may have ancient versions of these clients. If so, I would download and install the new version. But, since I have a slow modem connection, I would like to know which of them speaks smtps now, or if there is an other smaller mail client that does smtps.
Could you help me?

Finally I found Mozilla 1.5, which speaks SSL perfectly.
So, now I see the safe smtp relay works perfectly.

A new experience again showing that stunnel is the greatest: with stunnel it does not take more than a minute to fully setup a new secure service from scratch.
You configure stunnel once, then when you want a new safe service, you need not do anything else than start a new stunnel daemon to redirect the unsafe port of the service to the corresponding safe service port (say, port 110 to 995, 25 to 465, etc.), and you are done.

Just a note: it turned out that, as opposed to the sample setup published at this forum, YOU NEED NOT RUN STUNNEL ON CLIENT MACHINES, in order to use a safe smtp service of a server: new mail clients can perfecly communicate with stunnel on the server!