Re: Using "v=spf1/scope1,scope2,scope3 " as a scoping syntax

--Mark Shewmaker <mark(_at_)primefactor(_dot_)com> wrote:
> The upshot of all this is that:
>
> 1.  We'd have wiggle-room for people to define a senderID-type PRA
>     scope in a separate document, without the need to bump the
>     version string.
....
> So this is a change in the sense that all libraries would have to be
> updated, but not in the sense that it would change the meaning of any
> currently-published records or any records that would be published
> in the near future.

Well.  If all the existing, published, running code has to change, that's a 
tall barrier.  At that point it makes little difference whether you change 
the number, I think.

> I think this is a better solution than doing scoping with modifiers, as
> the latter would either require positional modifiers, (ugh), or it would
> require allowing multiple spf records with differing scoping modifiers,
> which is not backwards compatible with the current spf libraries that
> would see that as duplicate records and return permerror.

I agree that this is (slightly) better than scoping with modifiers, but 
still has the same problem.  We are changing the spec out from under folks 
who have published working code.

There is really no way to ensure that people won't go an misinterpret your 
v=spf1 records, or even your spf2.0/scopeA record if they have a scope that 
was not covered before and they feel it's substantially similar to the 
scope you are publishing.  If asking them politely not to doesn't work, 
giving them some new feature to the language probably won't work either.
I don't really have a strong preference as to whether scope is a modifier 
or a macro, but I do have a strong preference to not retroactively change 
the v=spf1 spec.  Whether domain owners have to change, or library writers 
have to change, or both, it doesn't much matter; we are changing a working, 
production spec out from under them.  Why not just call it spf2 if you are 
going to change the rules?

> (I do recognize however, that using positional modifiers and a more
> difficult-to-read record may allow publishers to put a single
> mfrom,pra,helo-scoped set of rules in one record instead of 3,
> compressing things such that everything fits in UDP size requirements,
> where that might not be possible with multiple TXT records.)
>
> --
> Mark Shewmaker
> mark(_at_)primefactor(_dot_)com
>
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--
Greg Connor <gconnor(_at_)nekodojo(_dot_)org>