SPF mail filter implemented at Microsoft and others

[Cory]

I have a coupe clients who have bonked into an interesting problem you all might want to be aware of. Microsoft implemented SPF on their inbound servers and I think others like AOL and Yahoo did too. SPF is a new filter protocol that looks back at the DNS server of the sending domain for an SPF entry and if the sending server’s IP isn’t found it blocks the email! Usually if it’s something like utahconnect.com (a fictional ISP in Utah) the ISP has made the necessary changes but for user who have their own domains who use their ISP’s SMTP server it’s a problem and they need to use the SMTP server of whoever hosts their domain. In a nutshell if you mix things up at all you're likely to have problems. SPF requires that you use the SMTP server specified in your DNS record. Even if you auth on a different server it won't matter. I mention this because I often use odd addresses and such for sending reports from ME and now I have to do it according to the book.

 

There's more too it of course and I've boned up on it a bit so feel free to ask questions if you like. On the plus side if everyone gets on board with SPF it could be the end of spam as we know it.