Reverse DNS Practice for Mail Server

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1

In setting up a mail server, what should we setup as a reverse DNS?
mail.mydomain.com
or
mydomain.com

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.

2

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

3

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.

4

5

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.

jaap.nl
cp.jaap.nl = hostname
client1.com
and client2.net

When I send a mail from jaap.nl, client1.com and client2.net my “Helo” respose will always be cp.jaap.nl so the reserve DNS should point to this domain.

When

6

Yes, we own the IP :slight_smile:

7

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

mail server – mail.mydomain.com
host – mydomain.com

8

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:

hostnamectl

Exim use this hostname for “Helo” header.

9

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