Re: [spfbis] Local macros strike again, was Suggestion...

Hi Murray,

I guess it all depends on how its written, but my only concern is that 
no one should get bent out of shape about trying to implement a 
"default rule" that would apply to all. I say that from the point of 
view that REJECTION is a strong part of SPF and this best guess idea 
can only serve a purpose for "reporting," at best, for one data point:

     The sender and receiver are part of the same network.

If this was a fundamental concept for all, i.e. part of the spec, then 
I can see the default "rule" applying for filters and IMO, we really 
never would need SPF.

But that is not an SMTP setup operational requirement, so I find no 
value in this default rule other than getting some "interesting data 
point" about the sender network setup.  The Sender/Receiver is part of 
the same network. So what?  It means nothing, at least I don't see it 
unless a NON-SPF logic is done to see if the MX is black listed or 
doesn't exist.

Per SMTP, an MX is not a requirement and we use a fall back to the A 
record.  If that fails, depending on the implementation it could be 
filtered. i.e. many systems use a "NO MX/TRIED A record Once" concept 
when sending mail.

--

Murray S. Kucherawy wrote:
>> -----Original Message-----
>> From: spfbis-bounces@ietf.org [mailto:spfbis-bounces@ietf.org] On Behalf Of Hector Santos
>> Sent: Wednesday, January 18, 2012 2:46 AM
>> To: spfbis@ietf.org
>> Subject: Re: [spfbis] Local macros strike again, was Suggestion...
>>
>>> AFAIK, t-online.de never published SPF records.  Some implementers
>>> leveraged SPF built-in functions to make "best guesses" about domains
>>> lacking SPF records.  This tactic is found in many SPF implementations
>>> as it will be for years.
>> Who?
>>
>> This must be completed isolated.
> 
> It's not.  A Google search for "best guess SPF" comes up with numerous records, and I've seen it referenced in white papers.  And I know for a fact that Gmail uses it.
> 
> The best definition I've seen is here: http://www.openspf.net/FAQ/Best_guess_record
> 
> I think part of the -bis effort should include an appendix that talks about this, albeit informatively, just so that a real consensus definition exists someplace.
> 
> -MSK
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> 

-- 
Hector Santos, CTO
http://www.santronics.com
http://santronics.blogspot.com