Re: DNS Forwarders - weird question

From: Herb Martin (news_at_LearnQuick.com)
Date: 12/21/04

  • Next message: Steve Grosz: "DNS stops responding issue" 
    Date: Tue, 21 Dec 2004 15:01:49 -0600

    > I attempt to resolve www.bigcompany.com, which obeys the conditional
    > forwarding and is sent to bigcompany's DNS servers. Unfortunately, their
    > servers don't resolve their own website (eh?) and it fails. What I really
    > want to do is specifiy a handful of exceptions (such as this one) which
    > should be sent to my ISP's DNS servers instead of bigcompany's DNS
    servers.

    The name www.bigcompany.com really is a domain
    (it may not be a zone) and you should be able to forward
    it conditionally.

    You can also create direct zones for each of these.

    What happens when you do this? What errors? Turn
    on debug logging if necessary (to trace the outgoing
    requests)....

    The sugestion (in another thread) of making a seconary
    is a poor one as you have surmised:

        It's a big zone -- which implies that it will have frequent
                changes and you cannot directly modify a secondary so converting
    it
            to a Primary is not likely to be useful

    > Yes, I know it's not nice, but believe me when I say that bigcompany is a
    > *big* company and I've got no chance of getting this changed!

    As to something this obvious though, they should fix it.

    Were you to have said, we cannot reach their web site
    with JUST "bigcompany.com" as the name then we would
    both understand the likely reasons for this and why they
    might not change it. (DCs all register this name.)

    But notice, the use of the bare domain name for either
    a web server or an email server is a very common
    example of the indistiguishability of a "domain" and
    a "machine name" (from the outside.)

    There is some mistake (or bug) if you cannot
    forward this conditionally. 

    -- 
Herb Martin
"Daern's Instant Fortress" <daern@hotmail.com> wrote in message
news:elv5Ys45EHA.828@TK2MSFTNGP14.phx.gbl...
>
> "Herb Martin" <news@LearnQuick.com> wrote in message
> news:uSqcTh45EHA.824@TK2MSFTNGP11.phx.gbl...
> > "Daern's Instant Fortress" <daern@hotmail.com> wrote in message
> > news:e7b6BI45EHA.1564@TK2MSFTNGP09.phx.gbl...
> >
> >> servers. This works fine.
> >>
> >> We now require to resolve hosts on the parent company's network.
> >
> > Conditional Forwarding would be the standard
> > answer since you have Win2003 (the feature is
> > new.)
>
> Yup. Conditional forwarding works great, apart from this situation.
Picture
> the scene...
>
> I attempt to resolve www.bigcompany.com, which obeys the conditional
> forwarding and is sent to bigcompany's DNS servers. Unfortunately, their
> servers don't resolve their own website (eh?) and it fails. What I really
> want to do is specifiy a handful of exceptions (such as this one) which
> should be sent to my ISP's DNS servers instead of bigcompany's DNS
servers.
>
> Yes, I know it's not nice, but believe me when I say that bigcompany is a
> *big* company and I've got no chance of getting this changed!
>
> >
> >> Fortunately, all of their hosts are in the form host.bigcompany.com
which
> >> means I can add a DNS domain forwarder for *.bigcompany.com to point to
> >> their DNS servers and all is well. Their hosts resolve off their DNS
> > servers
> >> and the rest of the internet resolves off our ISP's hosts. This works
> >> well
> >> and I was happy until...
> >>
> >> It turns out that some hosts (notably www.bigcompany.com) *do not*
> >> resolve
> >> on their internal DNS servers. Thus when my DNS server forwards these
> >> requests to bigcompany's internal DNS servers, it breaks. The annoying
> > thing
> >> is that some other sites (e.g. intranetsite.bigcompany.com) resolve
> >> differently from the internet than they do from bigcompany's internal
DNS
> >> servers. (I need the addresses resolved on the internal network).
> >
> > If you can identify those hosts (the public list is likely
> > a small subset) you can set a more specific condition
> > on JUST those hosts to point to your ISP or even directly
> > to theirs.
>
> How would I do this? I've not found a way of making it that granular in
> Windows 2003.
>
> >> Frankly it's a right old mess and I'm a bit stuck on how to do this
with
> >> Windows 2003 DNS.
> >
> > (More) Specific Conditional forwarding.
> >
> >> Have any of you DNS gurus got any suggestions for other avenues that I
> >> can
> >
> > You were almost there yourself.
>
> Thanks :-) I'm glad to hear it...
>
>
  • Next message: Steve Grosz: "DNS stops responding issue"

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