MX dot was (Re: [ietf-dkim] TXT wildcards SSP issues
steve at blighty.com
Sun Jun 3 10:03:28 PDT 2007
On Jun 3, 2007, at 9:51 AM, Douglas Otis wrote:
> On Sun, 2007-06-03 at 08:58 -0700, Steve Atkins wrote:
>> (Still way OT, but it's more interesting than SSP, eh?)
>>> IMO it's a really odd idea as it causes DNS root queries by
>>> compliant MTAs and changes the semantics of MX (now all of a
>>> sudden MX
>>> relates to sending mail).
>> No, it shouldn't cause root queries.
> Paul Vixie was fairly convincing in explaining why this construct
> significant trouble when used with SRV RRs for indicating "No
> The SRV draft even documents the meaning of the "." construct from
> inception. Still, software must exclude interpreting this as a valid
> host. When seen as a valid host too often, this construct can not be
> safely used, even when initially defined as "No Target." For the MX
> record, this field is defined as a valid host. Use of this construct
> would be expecting software to have the foresight to exclude ".".
> Yahoo gets a fair number of queries for "http://www.yahoo.com" A IN
> records which was fixed with a cname. Ignorant software is
> why expect otherwise?
This is straying a long way from relevant to DKIM, so I'm not going to
try and explain the basics of DNS here.
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