SPF Records (Sender Policy Framework)

[greg]

Recently we noticed that some of our non-customer domains weren't sending email to Hotmail accounts. There were no errors, no bounced emails, and Hotmail wasn't even putting the emails in a junk folder. They simply were not showing up, and seemed to be getting lost somewhere in the black hole of the internet.

Well, a few minutes of research led us to the issue: the DNS of our mail server was not configured with an "SPF" record. DNS records are set at the registrar level, so you change it wherever you bought your domain (not where your site is hosted).

Here's some good information on SPF records, including a wizard for creating your own quickly: http://www.openspf.org/