pfSense

Same error in system log with 2.1-RELEASE version.

That would be because your port 587 is not accepting secure connections. In a typical port 587 setup the connection is first established (unsecured) and then a STARTTLS command is sent. As it stands the existing library does not cater for that and tries to establish a secure connection to port 587, which would normally fail. Using port 465 would work as thats expecting a secure connection.

Ideally I guess, specifying port 465 should turn on a secure connection automatically. Any other port specified would be left as unsecure and if TLS is checked, then a STARTTLS would be issued after the connection has been established.

Hi Warren,

Thanks for the reply. The problem is that my email provider's SMTP server only accept 587 with TLS encryption¹.
On the other hand, it seems that 465 port is deprecated for SMTPS².

[1]: https://mykolab.com/clients#other
[2]: https://en.wikipedia.org/wiki/Smtps

(Sorry for my bad English)

Aitor Fraile wrote:

On the other hand, it seems that 465 port is deprecated for SMTPS².

Yes thats right, has been for awhile although the likes of GMail and similar still provide it due to old MUAs wanting to make use of it. Which brings up an interesting question, in pfSense a SSL connection should actually be done away with and only make use of STARTTLS.

I have a patch done, will commit it soon to HEAD.

Applied in changeset dd33fd4e8b3fb66f49ae8337823264ab0d13504c.