I’ve had the joy of trying to figure out why certain domain emails aren’t reaching certain users, especially Hotmail. Granted, SPF records and reverse DNS needed to be set up, but all the research and hard work are not paying off in the case of Hotmail/MSN/Live (all Microsoft brands) using a competing framework. All research points to SPF and SenderID not playing nice with each other…and Hotmail’s response? Starting at a mere $200, you can become a certified sender (Sender Score Certification) and reach over 3 billion inboxes.

I’ve found OpenSPF’s record wizard, Microsoft’s SenderID wizard (which appears to publish the exact same thing) and the SPF Query Tool helpful in setting up the correct DNS content. The following article also made this change easy. Since DNS Stuff went pay-for-service, I’ve had to resort to free DNS check tools like MXToolbox to look up things like reverse DNS and blacklist records.