Reverse Zones - Subnets?

[Nicolas Riendeau]

Hi!

Matt wrote:
> Hi,
> How do I do a reversal for only part of a subnet?  ie 192.168.1.1/29 ?
>  How do I just do a reversal for that part, instead of the whole
> 192.168.1.1/24 block?
> 
I do hope this address range is only used as an example and that you don't really 
want to do that for that address range... (-;

You should used RFC 2317, "Classless IN-ADDR.ARPA delegation" which is available at
http://www.ietf.org/rfc/rfc2317.txt for anything smaller than a /24.

Essentially what you do is that in the zone which includes the /24 you want to have 
delegated to another server you make CNAMEs instead of PTRs and these CNAMEs point to 
PTR in another zone.

There is a convention for creating these zones names in the RFC but some people use 
others, please check with your ISP if your ISP has control over that zone... If the 
zone name is built using the RFC 2317 convention or one similar, you must also add NS 
records so that it knows where the zone which contains the PTRs actually is (you 
delegate that zone to that server)...

In the new zone, hosted on the DNS which is actually going to resolve the reverse DNS 
for that range of addresses you create the actual PTR records..

Good luck (if your unlucky as I was when I had to get this done by my employer's ISP 
and hosting company, you're going to need it***) and have a nice day!

Nick

*** I actually had to tell them how to do it and find the info on how you do it with 
a microsoft dns (hosting company use that...).