On Thu, Mar 08, 2012 at 08:49:22AM +1100, Mark Andrews wrote: > Take SPF as a example. If providers had supported UNKNOWN format > then the SPF generation tools would have done UNKNOWN + SPF type > specific rather than TXT + SPF. My father used to have a saying: "If Johnny hadn't died, they wouldn't have buried him." Counterfactuals in engineering are just not that interesting. But anyway, providers (I am employed by one, FWIW) are not going to blindly support UNKNOWN on the input side. That's just an invitation to behaviour we don't understand and therefore cannot price correctly. More importantly, any plan that involves UNKNOWN types also automatically comes with unknown support costs. We will be forced to provide customer support for types we don't even know exist, and that will necessarily lead to unhappy customers. A plan something like the one John Levine has proposed is the only viable one, in my view. Best, A -- Andrew Sullivan ajs@xxxxxxxxxxxxxxxxxx _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf