The IANA still lists port 465, even referencing RFC 8314. I trust IANA more than “Mailgun,” yet I’m confused why people keep insisting that port 465 shouldn’t be used anymore when IANA clearly recommends it over 587
The linked RFC says it’s not an SMTPS port. Mail servers aren’t going to communicate on the port you reference. What port a mail clinent might use for a particular host. . What clients do you use that default to that Port when configuring it to use TLS?
I think theres a confusion about 465 and 587 now because of the one-time exception made by the IETF.
“It is desirable to migrate core protocols used by MUA software to Implicit TLS over time, for consistency as well as for the additional reasons discussed in Appendix A.”
Which means MUA software SHOULD use 465 instead of 587 making this the preferable port.
“SMTPS” is meant to be server-to-server connections. That was the brief purpose of port 465 as an smtps port that is no longer supported (and was never actually supported in the real world). What it’s used for now is submission, which is not what “SMTPS” was supposed to mean. So saying it’s not an SMTPS port is correct, but doesn’t mean it’s not a submission port.
Most end-user client software seems to prefer 465. If you run a mail server, you really must support submission on 465, and for that purpose it’s not deprecated. The confusion comes from the fact that people thought SMTPS meant “submission”.
I wouldn’t say this information is outdated. It simply is (and always has been) wrong.
This claims that port 587 should be used instead of port 25, which is outrageous.
Port 25 was and still is the port used by MTAs (server → server).
Ports 587 and 465 are used by MUAs and MSAs (client → server)
As the article doesn’t make a distinction between MTAs and MSAs at all when it comes to SMTP, it’s fairly useless in that regard.
. What clients do you use that default to that Port when configuring it to use TLS?