Classless Reverse zones

[Kevin Darcy]

Peter Anderson wrote:

> Hi ,
>
> I was originally thinking maybe I could create a static zone
> 116.10.in-addr.arpa and then have n.116.10.in-addr.arpa zone which would
> cover the subnet 10.116.32.0/22 (ie 10.116.32.1 - 10.116.35.254).
>
> I started off calling that zone 22/40.116.10.in-addr.arpa.

Why wouldn't you just have 4 zones, i.e. 32.116.10.in-addr.arpa,
33.116.10.in-addr.arpa, 34.116.10.in-addr.arpa, and 35.116.10.in-addr.arpa?

> Trouble is when a W2K updates it gets the SOA rec to work out which zone to
> update.
>
> The other trouble was I couldn't get the nameserver to recognise for example
> that for 10.116.43.1 to update zone 22/40.116.10.in-addr.arpa not
> 116.10.in-addr.arpa.

That's why you need to delegate to a lower level.

> Is this just not possible?
>
> I guess the other way around would be to make 116.10.in-addr.arpa dynamic
> and then define as many other static class C reverse zones separate to that.

Exactly.


- Kevin

> Any views or opinions presented are solely those of the author and do
> not necessarily represent those of Westpac Banking Corporation.
>
> -----Original Message-----
> From: Mark.Andrews at nominum.com [mailto:Mark.Andrews at nominum.com]
> Sent: Thursday, March 15, 2001 1:27 PM
> To: panderson at westpac.com.au
> Cc: comp-protocols-dns-bind at moderators.isc.org
> Subject: Re: Classless Reverse zones
>
>         Classless IN-ADDR using CNAMES is for cases where you can't
>         use classic delegation techniques and don't what to delegate
>         each individual reverse address.  It really shouldn't be
>         used for /0-/24.
> >
> > Has anyone created a zone with a 22 bit (or less) mask and $GENERATE?
>
>         Yes. You use 4 $GENERATE statements.
>
> >
> > I can't seem to get it to work and all the other examples I've found are
> for
> > subsetting a class C subnet.
>
>         That's what it was designed for.
>
> >
> > For example with a 22 bit mask do you have 4 NS recs in the parent domain?
>
>         Normally it's 4 consecutive, bit aligned, NS RRsets.
>
> >
> > This is all for internal DNS setup not connected with the internet at all
> > and we're getting lots of these subnets being used for dynamic updates,
> and
> > I'm trying to work out a way of reducing the number of zones.
>
>         I think you have enough information to do that if you still
>         want to.
>
>         Mark
> >
> > Thanks,
> >
> > Peter Anderson
> > Senior Communications Analyst
> > <Remove ETER from my address to reply>
> >
> > Any views or opinions presented are solely those of the author and do not
> > necessarily represent those of Westpac Banking Corporation.
> >
> >
> > --
> > Posted from mail.westpac.com.au [203.24.6.110]
> > via Mailgate.ORG Server - http://www.Mailgate.ORG
> >
> --
> Mark Andrews, Nominum Inc.
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com