-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Filipe Brandenburger Sent: Monday, August 03, 2009 10:40 To: CentOS mailing list Subject: Re: [CentOS] Split dns issues
Hi,
On Mon, Aug 3, 2009 at 10:27, Jason Pyeronjpyeron@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 around.
HTH, Filipe _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
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