PTR Record & Multiple domains? How to?

I have my MIAB domain on box.mymailserver.xyz and it’s set up to handle mail for 4 or 5 of my other domains.

Google is rejecting email from those domains for lacking a PTR record or not matching. My domains (with websites) are hosted separately from MIAB by Hostinger and I’m told they can’t add PTR records.

Am I missing something? Happy to give more information to help solve this.

You need a PTR record that points your MiaB server’s IP address to the mail server’s name, box.mymailserver.xyz. Without this PTR record you will have problems with email getting rejected from some destination servers like Google. I don’t know anything about Hostinger, but if they won’t let you set a PTR record then this will be an ongoing issue, I believe.

PTR records are something your hosting service needs to offer because the IP address belongs to them and they are in control of what PTR records can be set for their IP addresses. For example, my MiaB server runs in Linode and there is a way in their management UI to set the PTR record for my MiaB server.

If MiaB is also hosted at Hostinger as a VPS then maybe this can help:
how-to-point-domain-to-vps
At that link, search for “Setting Up Reverse DNS Record” in the web page.

If MiaB is not hosted at Hostinger, please provide more information regarding your MiaB hosting provider.

This is what’s confusing. My MIAB does have a valid PTR record, but I apparently need one for each of the other domains?

No, you only need a PTR record for the host name that is the mail server. For example, my email server might have the name, box.mymiab.com, but handle email for foobar.com and foobaz.com. There’s only one PTR record for box.mymiab.com. Think of this this way, when an email arrives from bob@foobar.com, but was sent by box.mymiab.com, the receiving server wants to do a reverse lookup on the IP address that sent it to confirm that it’s really box.mymiab.com that has this IP.

So (in broad strokes), for example let’s say the email arrives from IP 10.11.12.13 with “box.mymiab.com” in the header. The destination server will do reverse DNS on 10.11.12.13 and expects the answer to be box.mymiab.com. Otherwise, it assume you’re an imposter.

On the command line you can test this. Run the command: “host box.mymailserver.xyz” and it will return the IP of your mail server. Then take that IP address that is returned and run the same command with the IP, “host <ip address>”, and that should return the name of your mail server. If it does not, then the PTR record is not setup correctly.

You can test one of your Hostinger domains at MXToolBox “Email Health Report” tool here

You’ll get a detailed report regarding your domain including the mail server settings.
If everything is correct it should pass without any errors, if it does end up with an error
you can click the “More Info” to get more information about the error.

It might give you a more clear picture of what is the cause of the problem.

Thanks. I’ve used that tool and it only complains about an invalid value for my SOA record. But Google keeps telling me the message below. I am using the MIAB webmail interface for all email.

<some-email@gmail.com>: host gmail-smtp-in.l.google.com[2607:f8b0:400e:c0c::1a]
    said: 550-5.7.25 [2001:19f0:8001:425:5400:4ff:fe8f:f860] The IP address
    sending this 550-5.7.25 message does not have a PTR record setup, or the
    corresponding 550-5.7.25 forward DNS entry does not point to the sending
    IP. As a policy, 550-5.7.25 Gmail does not accept messages from IPs with
    missing PTR records. 550-5.7.25 For more information, go to 550 5.7.25
    https://support.google.com/mail/answer/81126#ip-practices
    q16-20020a638c50000000b005ce04177acbsi118182pgn.399 - gsmtp (in reply to
    end of DATA command)

Is it possible that your server is using IPv6 and that your DNS for IPv6 is not setup correctly? It has to be setup in both directions so doing DNS of the hostname returns the same IP that google sees and reverse DNS of the IP address (v6 or v4 I assume) shows the hostname.

I think you need to add a AAAA record to your box.mydomain.com,
curently it points to mydomain.com.

Yeah, I think you need to add that AAAA record to the server’s host name.

That was the answer! Thank you so much!

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