Reverse Configuration

[Kevin Oberman]

> From: Barry Margolin <barmar at alum.mit.edu>
> Date: Sat, 16 Oct 2010 13:24:37 -0400
> Sender: bind-users-bounces+oberman=es.net at lists.isc.org
> 
> In article <mailman.494.1287235344.555.bind-users at lists.isc.org>,
>  João Alberto Kuchnier <joao.kuchnier at gmail.com> wrote:
> 
> > Yes! I have eight domains in the same server using the same IP
> > distribution.
> > 
> > My rev file, have PTR entries for all of them. Its not necessary?
> 
> Yes, that's what I said:
> 
> > > While you can legally have multiple reverse entries for the IP, it's not 
> > > generally necessary or recommended.  Pick one of the names and use that 
> > > in the reverse entry.

To be completely clear, unless there is special software on the client
to deal with PTRs, you really only want ONE PTR for each address. Most
standard network tools tend to assume only one PTR per address and some
get very confused when multiple PTRs are returned.

I think that this is unfortunate, but there is too much software out
there (including many standard libraries) that make the same silly
assumption to things it can be changed. There is even an RFC saying
approximately this. Sorry, but I don't recall which one.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751