RES_BLAST

[Gauvin Repuspolo]

Hello Mark,
Thanks for the reply. With this, I think the picture is clearer now.

Thanks again everyone,
GovZ

On 10/24/07, Mark Andrews <Mark_Andrews at isc.org> wrote:

>
> > Hello danny and mark,
> > Thanks for all your answers.
> >
> > As of this moment, I cant really confirm whether RES_BLAST is really
> > implemented in the bind9 library. My limited skills, as far as I can
> > muster,  produced a "grep" result that RES_BLAST is only referenced to,
> when
> > the bind library makes the decision to execute the RES_ROTATE action.
> >
> > It seems that, RES_BLAST is not configurable also from "resolv.conf"
> file's
> > "options" settings. Being a newbie and all, I don't know if implementing
> a
> > simulaneous DNS lookup/query to multiple nameservers would prove to be
> > disastrous to a network, that is why bind9 seems to have no interface to
> set
> > the RES_BLAST option. (Again I may be wrong here.)
> >
> > I agree with you totally on the behaviour of some unix resolvers when
> the
> > first name-server listed becomes unreachable. Aside from this, I intend
> to
> > take a look at how RES_BLAST will handle situations where nameserver 1
> > returns an NXDOMAIN and nameserver 2 responds with an authoritative
> result.
>
>        All servers listes in resolv.conf are expected to return
>        consistant results.  RES_BLAST returns the *first* answer
>        whether it be NXDOMAIN, NODATA or records.
>
>        B.T.W. NXDOMAIN *is* an authoritative result
>
> > As for creating my own name server, is there a way for me to mimic the
> > effect of RES_BLAST using an IP forwarder. What I mean is, I setup an ip
> > forwarder, delcare two root zones (if this is even possible), within my
> > named.conf file so that the daemon is forced to lookup the forward list
> of
> > both root zones? Is it even possible to have two root zones? As for
> lwresd,
> > I am not yet familiar with it and will look into it also.
> >
> > I hope I make sense.
> >
> > Thank you all so much for the assistance,
> > GovZ
> >
> > On 10/24/07, Danny Thomas <d.thomas at its.uq.edu.au> wrote:
> > >
> > > >       RES_BLAST is available in lib/bind
> > >
> > > It would be great if you could make RES_BLAST the default in
> resolv.conf,
> > > as it would overcome the bad behaviour of the (unix) resolver when the
> > > first name-server listed becomes unreachable. Mind you, I don't know
> > > whether resolv.conf directives would come from bind, or whether it
> > > is code managed by the OS people importing bind code in the library.
> > >
> > > I know there are other approaches which do keep track of how quickly
> > > name-servers respond, and which soon learn when a name-server is
> unreach-
> > > able, but these involve daemons like a caching name-server or lwresd.
> > > So resolving is affected if the daemon dies.
> > >
> > > Danny
> > >
> > > --
> > >   d.thomas at its.uq.edu.au    Danny Thomas,
> > >          +61-7-3365-8221    Software Infrastructure,
> > > http://www.its.uq.edu.au    ITS, The University of Queensland
> > >
> > >
> > >
> >
> >
> >
> --
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org
>