Port 587 instead of 465 - Spam Issue / Setup / SSL Issue?

Question asked by YS Tech - 6/28/2024 at 4:04 AM

Unanswered

Should we now be using port 587 instead of 465 for SMTP?

I see quite a few pages explaining that port 465 is now a legacy port and we should be using 587. I assume this would also help with deliverability to Gmail, Outlook and the like?

I've setup everything and tested via mxtoolbox and have spf, dmarc and dkim all green, so all looks good there but testing deliverability via Warmly (no idea if this is any good), the tests go into spam for gmail, gsuite and outlook:

All other mail systems get delivered fine as you can see.

Could this be a port issue?

Also within eMClient in the SMTP security policy, I can only get this working using the "Use SSL/TLS on special port (legacy)" even though it says port 587. WHat ports should I be using if this is also legacy?

If I use "Use SSL/TLS if available" it just fails.

Thanks

5 Replies

Reply to Thread

Charalampos Michael Replied

6/28/2024 at 11:34 AM

Force SSL/TLS with 587 port is working for me. I have enabled TLS 1.2 and up only (no ssl on smartermail)

Nick Jansen Replied

6/28/2024 at 2:45 PM

That used to be the case, but now it's the opposite: RFC 8314 recommends Implicit TLS (typically port 465) over STARTTLS (Explicit TLS, typically port 587).

https://www.rfc-editor.org/rfc/rfc8314.html#section-3

Douglas Foster Replied

6/29/2024 at 7:47 AM

Normal mail delivery occurs over port 25, so interoperability with Gmail is not an issue. Client connections from Outlook or emClient use 465 or 587.

The critical issue is your port configuration. In Outlook, implicit TLS is labelled SSL/TLS. In SM, it is labelled SSL (but with plans to match Outlook labelling in a future release.)

Charalampos Michael Replied

6/29/2024 at 1:26 PM

Well it's all confusing due every company doesn't follow a standard. (Like RFC) If you google it it's more mess.

I use 993 TLS for IMAP and 587 TLS for SMTP (Force in both cases) and i'm super happy!

Kyle Kerst Replied

7/1/2024 at 3:35 PM

Employee Post

Typically port 465 was always associated with SSL, so I believe it's deprecation means that 587 (with STARTTLS) should be used in its place. Whether or not you disable SSL functionality will depend on your users and which protocols they support. Messages going into the junk email folder on third-party providers could be happening for a variety of reasons unfortunately - if you click on ...>Show Original on the received message in Google - do you see it failing any spam checks?

Kyle Kerst

Lead Internal Network/System Administrator

SmarterTools Inc.

smartertools.com

Back to Community Threads

Please leave this box unchecked

Reply to Thread

Enter the verification text