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I am lost in DNS and rDNS (PTR) record setting for the following scenario:

I have my main website example.com running in Digital Ocean at IP 192.0.2.4

In Digital Ocean control panel I have the following records:

imap CNAME mail.example.com.
smtp CNAME mail.example.com.
example.com. MX mail.example.com.
mail A 192.0.2.8

I have my mail server at 192.0.2.8 hosted in different server (say Linode).

Due to missing rDNS (PTR) record system generated mail are not delivered correctly.

From Digital Ocean docs I have found that Digital Ocean configures PTR based on host name so I renamed my droplets to example.com and changed hostname as well, so that it will create PTR records for me.

I don't have any clue what to do next as I am new to DNS stuff.

What am I missing here and how should I configure mail for this scenario so that there is no any problem regarding mail delivery and spamming issues?

Patrick Mevzek
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saki
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3 Answers3

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It's a little unclear what you're asking here, but I think you're saying that mail isn't coming through because of the missing rDNS.

The most likely answer is that you have to create a PTR record from 8.2.0.192.in-addr.arpa. to mail.example.com. That way, any host that is sending you email will see that the MX host matches forwards and backwards.

Patrick Mevzek
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catfood
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0

Your mail server is hosted by X and everything else (especially DNS) is hosted by Y.

From the requirements and the comments I see the problem:
You try to configure PTR on hoster X for an IP which is hosted by Y.

Answer:
You simply can't do that. That's why hoster X predefines the IP 192.0.2.4 instead of letting you enter IP 192.0.2.8.
The reason behind this is: IPs are also owned. And the PTR records are delegated in DNS to its owner (in your case to hoster Y). This has nothing to do with your domain and DNS management for example.com on hoster X.

Patrick Mevzek
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unNamed
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0

rDNS (PTR) record has to be set by the owner of the IP.

in your case 192.0.2.8 is owned by Linode.

so you have to find the reverse DNS setting on Linode control panel (if they offer that possibility). the value to put is: mail.example.com

You won't be able to set the rDNS on Digital Ocean since the mail server is not hosted there.

Patrick Mevzek
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exeral
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