28 May
2015
28 May
'15
3:37 p.m.
Subject:
Re: [44net] Bad MX records in the ampr.org DNS
From:
Don Fanning <don(a)00100100.net>
Date:
05/28/2015 02:45 AM
To:
AMPRNet working group <44net(a)hamradio.ucsd.edu>
On Wed, May 27, 2015 at 5:36 PM, Bryan Fields<Bryan(a)bryanfields.net> wrote:
Indeed, it is allowed to have some record like:
sub.domain IN CNAME another.domain
with
another.domain IN MX 10 hostname
But that is not what I mean. What is NOT allowed (by the spec) is to have:
name IN MX 10 mail
mail IN CNAME some.mail.server
So you can have a CNAME pointing to MX, but not MX pointing to CNAME.
Also, I don't understand the relation to the Google example. The support page you
mention gives a
list of MX records with names that are all A and AAAA records, no CNAME involved at all.
In practice, it appears that the CNAME works with some mail transfer agents. But bind9 is
complaining.
The literal IP address in an MX record results in 2 warnings, one that there is an address
in the MX record
and another that the 111.222.333.444.ampr.org is not defined. This of course is because
an address is not
expected there, and it is treated as a domain name relative to the $origin of the zone.
When your server has no associated name, of course you can assign one within ampr.org.
Also, when you want your server to SEND mail in addition to RECEIVING it, you need to have
a name and a
matching reverse, or many spamfilters will just drop your mail on the floor.
Rob
> > >That is not true at all. The previous paragraph states that it must
> > >process the entire FQDN and not many any inferences as to the domain's
> > >relationship with the FQDN.
>
>I'd like to try it out then, as I'm certain this doesn't work that way
in
>most
>resolvers for MX's. I've run into it before even.
>
>
I can tell you that GMail's MX RR's work in this fashion. I
don't need to
know their A record for my DNS. I just add their CNAME'ed MX records to my
domain files and my mail shows up. And my domain isn't hosted by them.
Just my mail hosting.
https://support.google.com/a/answer/33915?hl=en