On Wed, Jun 21, 2017 at 1:53 PM, Gene Shuman <[email protected]> wrote:

>
> It seems we have two choices available to us upon receipt of an invalid
> chain(which is defined as AS b= unable to be computed).
>
> 1. Simply stop adding further ARC headers.  Put arc=fail(or invalid) in
> the AR.  Further recipients will detect that the chain is broken as well,
> for the same reasons.  This is clearly the easiest solution.
>

If you put arc=fail in an AR and then the next hop ignores and strips the
AR (per spec), what good is it?

2. Add one further ARC-Set with an explicit cv=invalid in order to 'close'
> the chain, using the rule that Kurt has suggested.  This seems to have some
> benefit to me, but it's minimal.  It seems to wrap things up nicely, and it
> means that all ARC chains have a well defined cv value, which makes testing
> a little easier.  However the cost is clearly added complexity, both in the
> spec and implementations.  Is there any other tangible value to adding this
> final ARC-Set?  Does it help identify the failure point in the chain?  Is
> there any other benefit?  Kurt, can you speak to this?
>

A terminal ARC-set with cv=invalid is the only way to "close" a chain and
avoid reprocessing by each and every subsequent hop as far as I can see.

--Kurt
_______________________________________________
dmarc mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/dmarc

Reply via email to