DNAME understanding

[Andrew Sullivan]

On Fri, Dec 04, 2009 at 04:05:43PM -0500, John C Klensin wrote:
> applications that believe that it should be possible to get
> something back that matches when they do
> 
>    QTYPE=PTR, QNAME= 5.2.0.192.in-addr.arpa.

Well, ok, and I get your worry.  But to be honest, this is already
broken today, even if some either won't admit it or, like me, wish it
were otherwise and wish that we could do something useful with the
reverse mappings.

> Getting the above query to return all of the names in the same
> zone that have A RRs of 192.0.2.5 is just a matter of
> management.   In the general case, getting it to return all of
> the names that might have alias targets that ultimately point to
> that address is effectively impossible.

Yes, though not technically so (as you were careful to point out).  

I get the worry, however.

A

-- 
Andrew Sullivan
ajs at shinkuro.com
Shinkuro, Inc.