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).
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
someuser@yourbud:~$ postconf -d smtpd_banner smtpd_banner = $myhostname ESMTP $mail_name someuser@yourbud:~$ postconf -d myhostname myhostname = yourbud.co.za
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.
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.
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?