Sebastian Posner
2009-May-29 15:55 UTC
[Pkg-exim4-users] 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 -- Nur bis 31.05.: GMX FreeDSL Komplettanschluss mit DSL 6.000 Flatrate und Telefonanschluss nur 17,95 Euro/mtl.!* http://portal.gmx.net/de/go/dsl02
Andreas J. Guelzow
2009-May-29 17:53 UTC
[Pkg-exim4-users] Different nameservers for different routers/exim-instances?
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
Sebastian Posner
2009-Jun-03 07:10 UTC
[Pkg-exim4-users] Different nameservers for different routers/exim-instances?
"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 -- GMX FreeDSL mit DSL 6.000 Flatrate und Telefonanschluss nur 17,95 Euro/mtl.! http://dslspecial.gmx.de/freedsl-aktionspreis/?ac=OM.AD.PD003K11308T4569a