Quoting Michael Stone ([EMAIL PROTECTED]): > Well, it is vaporware. Until it's used by a noticable percentage of > hosts, it's irrelevant.
(1) Where I come from, the term "vapourware" means software touted far in advance of its availability. As noted, such is most emphatically not the case, here. However, moving on: (2) A relevant index for usefulness wouldn't be the percentage of _hosts_, but rather the percentage of _mail_ for which it's useful. This distinction is important: The utility of SPF lies in its ability to eliminate joe-jobbing, providing a means to validate MXes -- and, as I'm reasonably sure you'll have observed, forged mail's envelopes strongly tend to forge the domains of major (very large) mail-handling sites. Those sites happen to have been among the earliest adopters of SPF RRs in their DNS, largely because they are particularly motivated to protect their trademarks and their names. So, adding handling for SPF RRs in one's MTA yields significant advantages today, despite the technology being new, because _all_ of the forgemail claiming to be from aol.com, msn.com, hotmail.com, pobox.com, etc. can be detected all in one step. And that's a whole lot of spam, right there.
