Reverse DNS How-to

[keefe007]

I have searched this forum and I see many threads about reverse DNS. The only problem is that most of them only should part of the solution. Could someone who has sucessfully setup reverse DNS post a quick and full how-to?

It would be much appreciated! ;)

[jlasman]

What part of the solution are you looking for?

First of all, reverse DNS has to be delegated to you by your upstream provider. If they do that they should be able to tell you the method they've used and the name of the zone you have to set up on your server.

Then you have to set up that zone manually on the server, and create an entry for it in the /etc/named.conf file.

It's not quite as simple as it sounds.

Has your upstream provider delegated reverse DNS to you? If so, then what have they told you the zone needs to be?

Jeff

[jlasman]

There's a fairly good How-To here (http://www.ibiblio.org/pub/Linux/docs/howto/DNS-HOWTO) ; search for:

5.3. The reverse zone

But note also:

5.5. Why reverse lookups don't work.
5.5.1. The reverse zone isn't delegated
5.5.2. You've got a classless subnet

Unless you've got a full 256 IP#s assigned to you, then you're in that 5.5.2 section, and as you can see from the How-To, it's not an easy thing.

The official RFC can be found here (http://www.ietf.org/rfc/rfc2317.txt).

But you're probably better off if your upstream handles your reverse DNS for you.

Jeff

[keefe007]

The ISP has delegated the DNS for the full class C to us, but they did not tell me the method used.

I'll find out and get back on here.

Is there a way to do this via the Direct Admin interface?

I saw a few posts regarding this on these forums.

[jlasman]

Since they've delegated reverse DNS for the entire subnet to you, my first link should have in it all the information you need.

Jeff

[keefe007]

Alright that seemed to work like a charm.

Thanks!