Re: consensus call on MUST/SHOULD language for TXT records

[Daniel Quinlan <quinlan@xxxxxxxxxxxx>]

Andrew Newton <andy@xxxxxx> writes:

> Despite lack of agreement on the outcome, there is agreement on the 
> stated positions.  In the words of Olafur:
> 1) Specify everyone to be compliant at all times.
> 2) Specify clearly full complaint state and tolerate non-compliant 
> state during phase-in.
> 
> Position 1 is predicated on the notion that a future RFC will deprecate 
> the (use of the) TXT record in favor of the SPF2 record.  Position 2 
> demands that the TXT record be discouraged from use in the current 
> -protocol document.

I think Position 3 needs to be mentioned:

3) Remove SPF2 record and specify the use of TXT going forward.

and Position 4:

4) Schedule the deprecation of TXT now, not later.

Option 3 is so much superior to 1 and 2 from my perspective (MTA and
spam filter software) that will be doing many DNS queries, that it's
barely worth prioritizing 1 vs. 2.

That being said, in order of preference:

  3 >> 4 >> 2 >> 1

Put another way:

 - Doubling query volume is bad; inability to schedule in advance the
   end of querying both records is bad.
 - TXT is easier to deploy than SPF2 and no significant technical
   argument favors SPF2 over TXT aside from puritanism.

Daniel 

-- 
Daniel Quinlan
http://www.pathname.com/~quinlan/