Trouble configuring forwarders for reverse zones.

[M-lists]

Much obliged Chris: I'll give that a go.  Just out of interest though, how 
come you can't just specify a netmask?  It seems convoluted to have such 
different ways of specifying reverse forwarders for classfull and classless
Subnets.

C.



-----Original Message-----
From: Chris Buxton [mailto:cbuxton at menandmice.com] 
Sent: 08 April 2009 18:20
To: Callum Millard
Cc: Bind Users Mailing List
Subject: Re: Trouble configuring forwarders for reverse zones.

You would create a /16 or /24 parent zone. For example, you could use  
a zone named 1.1.10.in-addr.arpa. From that zone, you would delegate  
the /28 reverse zone using a syntax along these lines:

0/28.1.1.10.in-addr.arpa.	NS	1.other.name.server.
0/28.1.1.10.in-addr.arpa.	NS	2.other.name.server.
1.1.1.10.in-addr.arpa.		CNAME	1.0/28.1.1.10.in-addr.arpa.
2.1.1.10.in-addr.arpa.		CNAME	2.0/28.1.1.10.in-addr.arpa.
[...]
14.1.1.10.in-addr.arpa.		CNAME	14.0/28.1.1.10.in-addr.arpa.

You can simplify the creation of the CNAME records using a $GENERATE  
statement:

$GENERATE 1-14 1 CNAME 1.0/28

I have omitted the origin here for brevity.

Chris Buxton
Professional Services
Men & Mice

On Apr 8, 2009, at 8:45 AM, M-lists wrote:

> Apologies, I meant 10.1.1.0/28 not /24.  The addresses used are  
> arbitrary,
> as I don't like detailing my network topology unnecessarily.   
> Suffice to say
> we've had the */28 subnet dished out and have to work with it.
>
> Thanks for the suggestions in your last paragraph Chris, but I  
> didn't follow
> them entirely.  Does anyone know the syntax to forward reverse  
> queries for
> 10.1.1.1/28 on to a given host, or is it a bit more complex than with
> 10.1.0.0/16, as Chris' last paragraph suggests?
>
> Thanks again,
>
>
> C.
>
> -----Original Message-----
> From: Chris Buxton [mailto:cbuxton at menandmice.com]
> Sent: 08 April 2009 15:24
> To: Callum Millard
> Cc: bind-users at lists.isc.org
> Subject: Re: Trouble configuring forwarders for reverse zones.
>
> On Apr 8, 2009, at 3:00 AM, M-lists wrote:
>> One further thing, I'll be moving things around on our network soon,
>> and
>> this means we'll have a classless subnet soon.  So if we moved one
>> of our
>> Windows subnets to 10.1.1.0/24, how would I forward reverse queries
>> for this
>> subnet to say 10.1.1.1?
>
> When you say "classless subnet", what do you mean? A /24 is not a
> classless subnet as I understand the phrase.
>
> If you really do mean the same thing I do when I use that phrase, a
> subnet such as a /25 or /26, the first thing I would ask is why do
> this? You have 10/8 to work with. If you mean a classless subnet such
> as a /22 or /21, it's easier to just create the individual /24 reverse
> zones than to create a classless subnet reverse zone.
>
> In general, a classless subnet reverse zone relies on CNAME records to
> "move" the PTR record owner name to a new name, in an artificial zone.
> This requires a parent zone to create the CNAME records. (For zones
> larger than /24, use DNAME records instead of CNAME records.) So your
> BIND server might need a 10.1/16 zone, or possibly a 10.1.1/24 reverse
> zone - a parent zone using the standard naming convention that can
> then delegate artificial subzones elsewhere and can contain the CNAME
> or DNAME records needed to rename the PTR records into the subzone.
>
> Chris Buxton
> Professional Services
> Men & Mice
>
>