Pretty much ALL content here is at a "client level" and not a "server admin provider" level.
Correct, but as said, my first comment was only an addition in case they would use their own VPS or dedi (and such becoming a server admin).
Sorry, ALL the rDNS entry needs to do is point at an active DNS entry of a domain, and that domain does NOT have to be one you set, specifically in reference to your MTA. Is it better that it does.. sure... but it's not required... otherwise, how do you think multiple domains can send email from one base IP with a specific rDNS entry.
You're confusing things. The rDNS is just NOT pointing to some active DNS entry of a domain. For things to work correctly it needs to point to (preferable) the hostname of the server, like server.domain.com or the MTA, in which I mean for example mail.domain.com, being the name of the mailserver which you see when the HELO/EHLO takes place.
Is it required? No and I never said it was, neither is SPF/DKIM/DMARC, but rDNS is the first thing to do if you want to have your mail delivered correcly, that is what I said. Without rDNS mail will dissapear or get into spambox for sure.
As for the other domains, it doesn't matter, they all send via that ip and if you look at the header of the mail, you will see the hostname too, next to the domain which is used the send the mail (which indeed can be any domain on the server).
But the thing I was talking about extra, was if you have a domain on a server and you get your own ip with it (so seperate from the shared ip so you won't use the shared ip), then it can be even a more differenet situation. But lets forget about that, because that happens very little.
Once more it is NOT required to be an MTA...ALL it is required to be in a pointer at an existing domain,
WRONG!! And please don't put words in my mouth every time which I never said. I didn't say rDNS is required.
I said that if you use rDNS it muts be pointing to either the server's hostname or the MTA. We're talking mail delivery here, not general stuff.
The rDNS, also called PTR
can point to a domain name (certainly not a pointer!) but is almost solely used for good mail delivery and hence almost only used to refer to the system sending mail, hence like said, hostname or mta helo name.
Please stop arguing with me about this, because I know what it's a about, using it as professional hoster for 15 years as said. I know what I'm talking about when it's about mail delivery.
And I'll call BS here.. you will NEVER deliver reliable email to Hotmail (much less several other major providers) based upon that.... and THAT is a simple fact of life that almost EVERY admin (even those on shared hosting) have had issues with.
Well BS yourselve, otherwise explain how I have been able to do it with only rDNS and SPF setup? For years! Before I started using DKIM and we still don't use DMARC for everybody. People can, but don't use it, I only use it for my own domains, and I know it's giving forward issues, which you are afraid to get into, because I didn't here you about that, while it's a known fact of DMARC usage.
As for Google. Try to send a mail to Google without a correctly setup rDNS... goodbye.
The simple fact that you try to proclaim that simple rDNS is ALL you need to get reliable email delivery goes against what my first hand experience has shown AND what most other professionals state.
Again putting words into my mouth which I never said. Read better what it says, don't write what you THINK it says.
I've said to use that
as a test that rDNS/PTR is needed for reliable mail delivery above SPF and DKIM.
Ofcourse best practice is to use the combination of all, but without DMARC as this still has the forward problem.
And your first hand experience, does not weigh agains professional experience for years, that is a fact too.
First work as root admin with a shared hosting server yourselve, before telling others which have optimal mailservers for many years (without being in RBL's either) that they are wrong.
