SMTP Notifications issues with TLS/SSL & STARTTLS (resolved but curious)

[CatSpecial202]

Update: I changed the port to 465 and it seems like i can send notifications now. I had to save the notifications page BEFORE performing the test.

So, it works when both check boxes are ticked in Secure SMTP Connection and Validate SSL/TLS with port 465.

However, when i have port 587 it ONLY works when I have Validate SSL/TLS connection ticked and not Secure SMTP connection.

Why is that? Is one more secure than the other?

When I have both of the SSL/TLS options check and port 587 i get this error ...

Could not send the message to <email@removed.com> -- Error: Failed to connect to 
ssl://smtp.myserver.ch:587 [SMTP: Failed to connect socket: fsockopen(): Unable to connect to ssl://smtp.myserver.ch:587 
(Unknown error) (code: -1, response: )]

When i only have the first option Enabled SMTP over SSL/TLS checked and port 587....

I get this error:

Could not send the message to <email@removed.com>-- Error: Failed to connect to 
ssl://smtp.myserver.ch:587 [SMTP: Failed to connect socket: stream_socket_client(): Unable to connect to 
ssl://smtp.myserver.ch:587 (Unknown error) (code: -1, response: )]

When i only have the second one and port 587 it works ...

SMTP testing e-mail successfully sent

[johnpoz]

@CatSpecial202 there is another thread going over this topic actually..

587 is explicit use of tls, ie it would make a non secure connection and then use starttls to to convert to an encrypted session. While port 465 is implicit connection only, so no that checkbox would prob not work on port 587

here is the thread where that is being discussed, kind of as a side topic

https://forum.netgate.com/topic/190885/empty-message-id-in-smtp-test-email