On Fri, 22 May 2015 08:05:49 +0300, Antti Haapala
There's an issue about this at http://psf.upfronthosting.co.za/roundup/meta/issue562
I believe the problem is not that of the SPF, but the fact that mail gets sent using IPv6 from an address that has neither a name mapping to it nor a reverse pointer from IP address to name in DNS. See the second-first comment where R. David Murray states that "Mail is consistently sent from
The ipv6 reverse dns issue is being worked on.