Reverse DNS Practice for Mail Server

In setting up a mail server, what should we setup as a reverse DNS?

The reason I’m asking is that I’ve checked with both mail-tester and mxtoolbox. They seem to have a different idea on what should be in the reverse DNS ptr. In my case, both domain and sub-domain are in the same server sharing the same email address.

Thanks for any feedback.

Ptr only works if you own the IP. If you are unsure about that, then you don’t own it.

In addition to what jlguerrero is saiyng, usually is the hostname of the server you are sending email from. It’s a global record valid for all the mail domains you are using under this server.

Your reserve DNS needs to be the same as the answer from the mail servers:

If I have 3 users/domains and share 1 ip. = hostname

When I send a mail from, and my “Helo” respose will always be so the reserve DNS should point to this domain.


Yes, we own the IP :slight_smile:

Ok. It should actually be the host instead of the mail server?

mail server –
host –

In PTR record you must to use “something.domain.tld”, not only “domain.tld”, because it’s a hostname. You can view your actual hostname in “https://sub.domain.tld:8083/list/server/” or in “Static hostname” with:


Exim use this hostname for “Helo” header.

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