Inverse DNS with Multiple DNS servers

[Mark_Andrews at isc.org]

> 
> Hello:
> 
> I'm a newbie to DNS administration and can't seem to find an answer to
> what I think is a basic question; we are using Bind 9.
> 
> Example:
> A company has two domains that they are authoritative for.  There are
> two DNS servers, each authoritative for one domain.  There is an an
> entire Class C domain being routed to this company from its upstream
> ISP.
> 
> The upstream ISP has granted(?) in-addr.arpa resolution for this Class C
> to an IP of one of the nameservers, say .3
> 
> The other name server is .5
> 
> My question:
> 
> Does .3 have to provide reverse mapping for .5?  In other words, if
> domain1.com is served by .3 and domain2.com is served by .5, does .3
> have to list the hosts in reverse for its own domain as well as those in
> ..5?

	That would be the usually way to do it if there is one company
	involved.

	Mark
> 
> When I nslookup www.domain2.com, I get responses back fine.  But if I
> nslookup this same host by IP it fails... since I assume I haven't
> created the appropriate reverse listing on .3
> 
> Am I missing something real basic here?  How do I tell the world that .5
> also provides reverse-mapping for domain2.com?
> 
> Thanks very much for any assistance.
> 
> Mark
> 
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org