Should I use Reverse DNS (rDNS) with or without "www."?

Question

If I set up a rDNS entry for my server, should I enter just the hostname or should I include www.?

I assume that the A-Record for example.com and www.example.com point to the same server, of course. The site is running on www.example.com, if that matters.

I am asking because I have been told different stuff by different support members of my hosting provider. I am sorry that I can not give you a link to a resource with any of these opinions, as I am not even sure what to search for.

An answer from personal experience would be great, but I would prefer if someone here knows of an "official" document that states this.

Reverse DNS requires that you have a dedicated IP address. This would be a PTR record. If you are on a shared server, you would/should not set-up a PTR record. As well, use a CNAME record to point www.example.com to example.com. Example.com would have an A record and not sub-domains such as www. — closetnoc, Apr 22 '16 at 04:46

score 1 · Accepted Answer · answered Apr 21 '16 at 08:47

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The domain name returned from the reverse DNS lookup of the IP address should itself have an A record in its DNS record that points back to the IP address (in order to be "forward-confirmed").

So, in the case of a www subdomain, which is usually just a CNAME record pointing to the main domain, you should probably specify the bare domain. eg. example.com.

answered Apr 21 '16 at 08:47

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BTW- The OP should not be setting up a PTR record on a shared host. – closetnoc Apr 22 '16 at 04:46
@closetnoc thanks, I was talking about a server with an own IP – simonthesorcerer Apr 28 '16 at 10:40
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@simonthesorcerer I was not sure. We get people with varying levels of understanding here. I was just making sure since this seemed important. Cheers!! – closetnoc Apr 28 '16 at 14:26

Should I use Reverse DNS (rDNS) with or without "www."?

1 Answers1