There are a ton of questions related to this issue - and I have gone through almost each one yet this issue persists and I have no idea how to proceed further.
My mail server is setup with postfix, I have the corresponding A/AAAA records, etc setup including a PTR record from my IPv4 -> yourbud.co.za (my domain).
MXToolBox shows Reverse DNS does not match SMTP Banner
. The reason being the HELO/EHLO response does not contain the domain.tld
within the string. It does.
Requirements for SMTP server
- Postfix setup (dkim, dmarc, spf all setup too)
- A/AAAA records pointing yourbud.co.za -> ipv4/6 addresses
- PTR record pointing ipv4 (and ipv6 optional?) -> yourbud.co.za
Postfix (postconf)
someuser@yourbud:~$ postconf -d smtpd_banner
smtpd_banner = $myhostname ESMTP $mail_name
someuser@yourbud:~$ postconf -d myhostname
myhostname = yourbud.co.za
MXToolBox
You can find the MXToolBox MX diagnostics for my domain here. Further, dmarc, dkim & spf all report passes.
Root Problem (I need to solve)
Outlook and GMail are marking my emails as junk.
More Information:
According to this, and this, this, and this (and a few others) all suggest that having a banner mismatch will cause mail providers (Outlook, GMail, etc) to mark the emails as spam/junk which is what is happening.
You can find more information about my question & my setup here.My IP is not on any blacklist site.
According to this post, MXToolBox requires a subdomain handling mail, something like mail.yourbud.co.za
but this isn't a requirement as far as I can tell.
Why does Outlook/GMail still regard my mail as spam/junk?
yourbud.co.za
is a cannabis business that is causing the problems with their emails being marked as junk with Microsoft & Google. From purely technical perspective everything seems to be surprisingly good.mail.yourbud.co.za
?mail.example.com
andexample.com
treated the same as HELO names, and both are so widely used that penalizing one would cause more problems to the recipient. But @MichaelHampton usually has some interesting insights, so I'd expect to see some quality sources behind the claim and learn some more.