STARTTLS considered harmful

Posted Aug 19, 2021 19:09 UTC (Thu) by miquels (guest, #59247)
In reply to: STARTTLS considered harmful by chris_se
Parent article: STARTTLS considered harmful

> Has your experience with port 465 been any better in more recent years?

Well yes, at my ISP all of 25/465/587 work, and large mail providers like gmail etc are also not a problem.
Now I actually happen to work at said ISP as well :) so I just asked our main mail guy for some numbers as to the relative usage of 25/465/587 on our SMTP submission servers. That is, the servers that our customers connect to to send outgoing mail. Note that we require clients to always use TLS, either STARTTLS on 25 or 587, or implicit on 465.

port  % of connections
25	60.5
465	24.8
587	14.6