Hi,
On Fri, Jun 02, 2023 at 12:46:04PM +0100, Andrew Wood wrote:
> Can I clarify my understanding of an issue with a Debian Postfix server
> please. We have a mail server which is a VPS running Debian hosted by OVH.
> Its hostname is of the form vps-xyz.vps.ovh.net the PTR for the IP resolves
> to that.
This is an extremely bad choice of name for a mail server because it
looks like a default configuration of one of hundreds of thousands
of OVH VPSes.
Also, OVH is a notoriously bad email neighbourhood so don't expect
to be able to reliably get mail out of there and into inboxes at
Google, Microsoft and Yahoo!. OVH has a big spam problem (so do
most of the large, cheap hosters).
> The the issue is our server sends mail for our own domains and we are
> getting mail rejected from some recipient servers with 550 PTR rejected:
> Please use a non-generic PTR (in reply to RCPT TO command.
It is fortunate at least that they give some reasoning. You are
probably going to find a bunch more that just reject with no stated
reason, or silently file in junk folder.
> My understanding is that as we are sending email from our own domain e.g
> "example.com" its complaining because the PTR is ovh.net not example.com?
No, there is no requirement for the PTR record to match the From:
address of the email. They just want it to not look like a generic
OVH VPS.
> As its not recommended to have more than one PTR for an IP is there anything
> we can do about this given that our server handles mail for a couple of
> domains?
Just pick a domain that's related to you and make sure it resolves
correctly both ways. It can send mail for multiple domains, that's
not the issue. Your issue is very likely that your hostname ends in
"ovh.net". Do also set up SPF, DKIM and DMARC. After all that you'll
probably still have some issues.
Try the "mailop" mailing list for advice on deliverability issues
but I warn you now: the first advice from 90% of respondents there
will be to stop sending email from OVH IP addresses.
https://www.mailop.org/
Cheers,
Andy
--
https://bitfolk.com/ -- No-nonsense VPS hosting
