[CentOS] Split dns issues
jpyeron at pdinc.us
Mon Aug 3 16:07:35 UTC 2009
> -----Original Message-----
> From: centos-bounces at centos.org
> [mailto:centos-bounces at centos.org] On Behalf Of Filipe Brandenburger
> Sent: Monday, August 03, 2009 10:40
> To: CentOS mailing list
> Subject: Re: [CentOS] Split dns issues
> On Mon, Aug 3, 2009 at 10:27, Jason Pyeron<jpyeron at pdinc.us> wrote:
> > My worry is the A record for the outsourced mail service is
> out of our
> > control, if it were to change it would be catastrophic.
> Well, if you *must* use a name like mx.google.com for your
> MX, you could also set up an mx.google.com domain as
> authoritative in your domain, and then add an "A" record with
> your internal mail server there... It's not beautiful, but it
> should work.
I think this is a perfect solution as weighed against every thing else.
> Another alternative is to use "includes" in BIND, that way
> you could have "views" for your pdinc.us zone, then on both
> of them you would only have the MX record (which would be
> different on each of them) and maybe the SOA record (but you
> could also decide to keep that on the included file) and then
> an include to a file that contains the bulk of the records
> for the zone. Would that solve your problem managing views
> for that zone?
Too messy, as there are many changing records, and some are already klobbered as
described above and in previous emails.
> > I like the idea about the cname. Can a cname be used as a
> host for a MX record?
> Not according to the RFCs, but in practice it does work.
> Beware that you might stop receiving e-mails from very old
> and very buggy e-mail servers though (like maybe Exchange 5
> or very old Lotus Notes, but I don't think anyone still uses those.)
Doh. We use Exchange 5.5 SP4. (don't ask)
> > The other fear is the outsourced (showing ignorance on SMTP here)
> > might react badly to the client making a connection to a
> server with a
> > name different than they expected, as it looks like they
> are doing a name based virtual hosting.
> I don't think so, since SMTP only uses the name of the MX
> server for the TCP connection to the server's IP, nothing in
> the protocol later will use that name again. Virtual hosting
> is usually done by having the server accept e-mails to any of
> those e-mail domains on the same server.
I guess they are doing the weird naming thing so they can shuffle servers
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