On 6/15/2004 4:32 PM, Eric A. Hall wrote:
SPF is worth publishing, but the value for checking is marginal and
will probably stay that way.
I think this has been said about a million times before, but surely SPF
(etc) is, as things stand, only worth publishing if a sufficient proportion
of sites check it? If, as you suggest, the benefit in checking is low, the
benefit in publishing will remain small.
There are a few things that could change this relationship without the
proportion of checking sites suddenly going up.
1. Spammers move away from forged senders.
Benefit in publishing falls
2. Receivers more strongly weight their local policy against
non-publishers
Benefit of publishing increases
3. Publishers tighten their published policy i.e. for SPF move to
-all (or as we call it in our office "f**k-all")
Benefit of checking increases, which *may* increase the benefit
of publishing.
I believe we'll see some of these processes in action over the next few
months. But given that we know precisely nothing about the relative
strength of the effects, it's simply not possible to say what the outcome
will be. Hence much SPF (and MARID) evangelism must be faith-based. Now
that's not bad in itself, but it shouldn't be confused with engineering.
Of course one thing that could really change the interactions here would be
some regulatory change affecting a large proportion of hosts of the MTS :-)