EDNS, NOTIMPL and retrying query

[Mark_Andrews at isc.org]

> Hi, 
> 
> I have a problem with a domain (session.rservices.com, private domain
> not visible from the internet.) I am running bind 9.1.3, and cannot
> look up addresses in this domain. By using snoop/ethereal I can see that
> the sequence is as follows:
> 
> mydns  ->   theirdns   : A Query with edns optional RR
> theirdns -> mydns      : NOTIMPL
> mydns  ->   theirdns2  : A Query with edns optional RR
> theirdns2 -> mydns     : NOTIMPL
> 
> Shouldn't my dns server send a new request to the same server without
> the edns optional RR? It never does. If I use 
> "dig foo.session.rservices.com @theirdns" it works, as dig will not use
> the edns extensions.
> 
> On another of my dns servers connecting to the same domain (But
> different location and different name server.) the results is
> different:
> 
> mydns  ->   theirdns   : A Query with edns optional RR
> theirdns -> mydns      : FORMERR
> mydns  ->   theirdns   : A Query without edns optional RR
> theirdns -> mydns      : A response
> 
> So, can I make my dns server resend the query without the edns
> optional RR on a NOTIMPL reply? The vendors dns server is a very
> limited implementation and I don't think there is any hope of us
> changing that.
> -- 
>   -asbjxrn
> 

	9.2.1rc1

1206.   [bug]           SERVFAIL and NOTIMP responses to an EDNS query should
                        trigger a non-EDNS retry.

--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org