Pkg exim4 users - May 2009 - Different nameservers for different routers/exim-instances?

Hello,

Did anyone of you ever run into the need to resolve names for one router
different from the other ones?

Something like an internal mail gateway with external connectivity to deliver
mails to the internet; but for some obscure (internal) routing-targets you need
to get the routing data from some DNS entries that are not available on your
standard resolving nameserver, and the nameserver wich is able to supply the
needed data is not capable of resolving "the internet".

At the moment the only possibility I see is to install a cronjob that frequently
calls the needed data from the nameservers that supply them and write it to file
which is included in the respective router by exim..

I don''t like this solution; as soon as the config is ported to some
other server it won''t work anymore, because someone forgot that there
has to be this cronjob.. Any other/better ideas?

Thanks in advance!

Sebastian
-- 
baboo
-- 
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On Fri, 2009-05-29 at 17:55 +0200, Sebastian Posner
wrote:
> Hello,
> 
> Did anyone of you ever run into the need to resolve names for one router
different from the other ones?
> 
> Something like an internal mail gateway with external connectivity to
deliver mails to the internet; but for some obscure (internal) routing-targets
you need to get the routing data from some DNS entries that are not available on
your standard resolving nameserver, and the nameserver wich is able to supply
the needed data is not capable of resolving "the internet".
> 
> At the moment the only possibility I see is to install a cronjob that
frequently calls the needed data from the nameservers that supply them and write
it to file which is included in the respective router by exim..
> 
> I don''t like this solution; as soon as the config is ported to
some other server it won''t work anymore, because someone forgot that
there has to be this cronjob.. Any other/better ideas?
> 
I think the question is why do you need two DNS servers in play here.
DNS servers can be set up to be dual (or multi-) horizon so they will
give different answers to different clients. So you could have A DNS
that knows everything but sends the obscure info only to internal hosts.

Andreas
-- 
Andreas J. Guelzow, PhD, FTICA
Coordinator, Mathematical & Computing Sciences
Concordia University College of Alberta

"Andreas J. Guelzow" <aguelzow at math.concordia.ab.ca>:

[Get exim to use zoneinformation from two different nameservers]
> I think the question is why do you need two DNS servers in play here.
> DNS servers can be set up to be dual (or multi-) horizon so they will
> give different answers to different clients. So you could have A DNS
> that knows everything but sends the obscure info only to internal hosts.
That''s a decision on OSI-Layer 8. NS A is maintained by Unit A, NS B by
unit B.

Installing a nameserver with different views would put *me* in the
responsibility to maintain lists of clients that need view a, b or c - this is
not feasible.

I could set up my own private little nameserver on my mail-box perfectly fit for
my needs, but the box does also offer other services which need "pure"
DNS resolving, so this isn''t really an option.

Besides.. I don''t want to have infrastructure services running on every
second machine, this wouldn''t be maintainable, especially given that
the tech-staff currently operating these boxes is already "technically
challenged" with the current complexity.

I would even be happy with the possibility to give the whole exim-instance
another nameserver to use; then I could at least split-horizon the MTA on this
machine and set up static mail routing for the domains in regard to go to the
other "virtual exim" which uses the "sick" nameserver..

Sebastian
-- 
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