Re: misconception in SPF

On Tue, Dec 11, 2012 at 9:46 AM, John Levine <[email protected]> wrote:
>>No. I know some do, but I think it's a minority. (Among commercial spam-filters used mainly
>>by corporations, that is. It could be that some of the larger ISPs block SPF fails outright,
>>which would skew the picture.)
>
> No ISP I know does that.  The false positive rate is much too high,
> since publication of a -all record is highly correlated with
> assertions that all forwarding is evil, which is of course just wrong.
>

I concur with John - The false positive rates, misconfigurations in
records, etc. are one of the reasons for the development of DMARC and
the buy-in by major mailbox providers (See announcement by MS
yesterday for outlook.com implementing DMARC and switching from SID to
SPF - http://blogs.office.com/b/microsoft-outlook/archive/2012/12/10/outlook-com-increases-security-with-support-for-dmarc-and-ev-certificates.aspx)

I'm not sure I agree with John that a -all record is somehow an
assertion that all forwarding is evil. I'll save that discussion for
drinks the next time I see him.

Mike