> On Dec 14, 2017, at 3:27 PM, Grant Taylor via mailop <mailop@mailop.org> > wrote: > >> In practice, very few receivers implement SPF policy (except -all by itself >> for domains which don't send mail as a special case). > > What sort of data / experience do you have to back that statement up? (I've > not looked for any.)
I don’t know there’s any published data. However, I’ve examined thousands (hundreds of thousands?) of lines of SMTP log files, monitored hundreds of sends to millions of emails and have been paying attention to what does and does not get email delivered / not delivered for more than 15 years. My experience matches Brandon’s; there are very few places and no one of any size that is rejecting solely on a SPF -all record. My recommendations are ~all is fine as is -all. Some folks are more comfortable with one or the other. In practice they give senders the same practical recommendation. Know, too, that at least one Very Large Provider (covering up to 70% of addresses on some mailing lists) not only doesn’t bounce mail with a -all, they make some guesses about SPF and will label mail “SPF (best-guess) Pass” for some cases. Cases that I’ve investigated include a rDNS domain match between the connecting IP and the 5321.from domain as well as the sending IP also being the MX for the domain. In other words, you can ask for whatever policy you want. But no one has to comply with it. And, the current reality is that few major receivers are complying with those requests. laura -- Having an Email Crisis? We can help! 800 823-9674 Laura Atkins Word to the Wise la...@wordtothewise.com (650) 437-0741 Email Delivery Blog: https://wordtothewise.com/blog
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