Re: [courier-users] MX should not point to a CNAME?

[Matus U. - f. <uh...@fa...>]

>On Thu, Jan 22, 2015 at 3:06 PM, Jeff Potter <jpo...@co...>
>wrote:
>> The other issue: a sending server can resolve the CNAME and rewrite the
>> address on you. I saw this years ago.
>>
>> E.g.:
>>
>> foo.com with a CNAME of “bar.com”
>> foo.com with an MX of “some-good-mailserver.example.com”

On 22.01.15 19:23, Jan Ingvoldstad wrote:
>Well, this is in direct violation of the DNS specification for CNAME. When
>foo.com is a CNAME, it CANNOT have any other records, so the behaviour of
>that MX record is undefined, whether it breaks in the way you describe or
>foo.com simply won't resolve, is too risky to rely on.

I believe that was supposed to be:

foo.com with a CNAME of “bar.com”

I have also seen the mailserver to rewrite the domain when CNAME was found,
unrelated to other records...

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