The Sender Policy Framework, the hot shot retired or revived?

Spam issues has never been easy. We know that. The ancient IT heroes have told us stories how SMTP was not meant to be built secure. But now, in the era of gadgets, mobility, and messaging everywhere, I am sure it is worth to take a look at what we have as anti spam.

I am running exchange servers for in the office. Those servers are great. Really, you can have everything you can expect from a mail server with so many pluses. With exchange you will have much more than mail, you will have the whole business attached with you.

Well, there is a slight thing you need to know. It's the capability to handle spam emails that is a little short there. Exchange 2003 is not hot with it. With me, I put a GFI Mail Essentials installed in the back end. With a litte fine-tuning, everything is fine. Until then..

My boss was a bit pissed off by some emails he sent did not delivered to some recipients. He sent it from his phone with IMAP protocol. I definitely looked very stupid because the recipients were in the same domain. Our domain. OK, I won't assume a thing. I needed to look. Then I found the email was sitting there in the Junk Mail folder. Yes, I frowned. How come emails from the same domain get into junk folder?

I am sure to fix this, I need to mock around the exchange server, again.

My first suspect was the Intelligent Message Filtering in the Exchange Server. To provide proof I have to change the setting in the Global Setting - Message Delivery. Change some setting, increasing the SCL level for Junk Mail. No Luck.

Well, how about disable the Intelligent Message Filtering filter from the SMTP at all the servers. Yes I did it, and still no luck.

My second suspect was the GFI Mail Essentials settings. I change the Sender Policy Filter level to Low, and voila! it works.

Well yea, it works, now but still leave me with wonder, why the heck this SPF marks emails from cellphone in the same domain as Junk? I checked the SPF text in my DNS. it allows all to send email. So it should be ok. But why not???