Classless in-addr.arpa delegation.

[Jay Nugent]

Greetings,

On Mon, 28 Aug 2000, Kevin Darcy wrote:

> 
> Wait a minute! What zone are those PTR's contained in? The C-class
> zone? That's *bad*news*. Not only are you blinding your own clients to other
> PTR's in that same C-class range, but you're propagating bogus Authority
> Section data, thus potentially blinding *other*people's* nameservers to other
> PTR's in that same C-class range, not to mention misdirecting traffic to your
> nameservers.
> 
> There's a reason that RFC 2317 is a BCP.

   You are only partially correct.  Yes, I am indeed blinding my clients
from a *small* piece of the Internet, precicesly the other half of the
class-C that I'm on.  Should my customers need to resolve those other 128
hosts, then I'll look for a more elegant solution.  Thuis far that has not
been a problem.

   As for "propagating bogus Authority Section data".... Absolutely not!
The ISP is authoratative for the class-C.  Then only send the 128
addresses *I* use to *me* to reverse resolve.  The rest of the block the
ISP does with as they would any other block, usually entering their
customers hosts names into the DNS for them.  I am NOT providing bogus
data.

   However, if there is a better way, I'd certainly like to see some
sample zone files... :-)

      --- Jay


> Jay Nugent wrote:
> 
> > Greetings,
> >
> > On Mon, 28 Aug 2000, Kevin Darcy wrote:
> >
> > >
> > > Doing RFC 2317 on a non-bit-boundary is a little unusual, but certainly
> > > workable.  That's why I say that "classless delegation" is somewhat of a
> > > misnomer -- it's really *aliasing* rather than "delegation" _per_se_.
> > > All your ISP needs to do is add 10 CNAMEs to the
> > > 192.204.212.in-addr.arpa zone:
> > >
> > > 51    in    cname    51.rev.jdimedia.nl.
> > > 52    in    cname    52.rev.jdimedia.nl.
> > > 53    in    cname    53.rev.jdimedia.nl.
> > > (etc.)
> > >
> > > I've used "rev.jdimedi.nl" here as the "container" zone for the PTR
> > > records, but you could use *anything* mutually-acceptable between your
> > > and your ISP, as long as it's a zone delegated to, and controlled by
> > > you.
> >
> >    Or just have the ISP do the following which will send all PTR lookups
> > to YOUR nameserver.  Then on your nameserver you use conventional PTR
> > records to do the final resolve.
> >
> > At the ISP:
> > -----------
> > 51    IN     NS     ns1.yourserver.com.
> > 52    IN     NS     ns1.yourserver.com.
> > 53    IN     NS     ns1.yourserver.com.
> >
> > In your nameserver:
> > -------------------
> > 51    IN     PTR    larry.yourdomain.com.
> > 52    IN     PTR    moe.yourdomain.com.
> > 53    IN     PTR    curley.yourdomain.com.
> >
> >    I do this for my 128-host address block.  My ISP didn't even know it
> > could be done.  They learn something new from their customers every day
> >   :-)
> >
> >       --- Jay

             
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