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Re: [spf-discuss] Re: Another test case for the test suite...

2007-01-10 08:54:12
On Wed, 10 Jan 2007, Julian Mehnle wrote:

query for TXT records
if there aren't any valid SPFv1 records, then query for type99
proceed with record selection as per section 4.5

Yes, this is technically doing record selection twice, but that isn't
ruled out by RFC4408.

That is what pyspf does.

Interestingly, this is exactly the reverse of what Mail::SPF does, which 
is:

  query for SPF-type records
  if there aren't any valid SPFv1 records, then query for TXT-type
  proceed with record selection as per section 4.5

I don't recommend that because there are quite a few braindead
DNS servers which TIMEOUT for unknown record types.  By checking
type 99 first, you get an long delay for the SPF check.  While you
seem to have run into a TIMEOUT for type TXT, it is much more rare.

pyspf code has a note to switch to type 99 first when timeouts for
type 99 become less common.

-- 
              Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
    Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.

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