Newbie: in-addr.arpa file for a C Class

[Barry Margolin]

In article <ca2o7q$2l9o$1 at sf1.isc.org>, bela at webnet-x.com (belacyrf) 
wrote:

> Can anyone point me in the right direction.  We have a couple reverse
> files 3.2.1.rev for a few of our c classes.  In these files we specify
> the individual reverse entries for each IP.
> 
> How do I set up a single in-addr.arpa entry for a full C Class.
> 
> For example.  I just want to set up an "in-addr.arpa" file for the
> 3.2.1 c class... I dont want to do it by IP.  If I'm not making sense,
> I'm sorry, I'm pretty new. thanks

Do you want the reverse entry for all the addresses in that network to 
map to the same name?  You can do that with a wildcard:

* IN PTR generic.yourcompany.com.

However, I don't recommend doing this.  Many applications that perform 
reverse lookups try to verify them by doing a forward lookup of the name 
that they get back, to see if it matches the original address.  But when 
they look up generic.yourcompany.com, they probably won't get back the 
original address, unless you give it 256 A records.

A better solution may be to use $GENERATE:

$GENERATE 0-255 $ IN PTR host-$.yourcompany.com.

will automatically create:

0 IN PTR host-0.yourcompany.com.
1 IN PTR host-1.yourcompany.com.
....
255 IN PTR host-255.yourcompany.com.

You can use a similar construct in the forward zone to create the 
corresponding A records.

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***