Magic 8 Ball Spam Filter: Outlook Not So Good · Wednesday, February 20, 2008

For years, I have been able to keep my personal email address virtually spam-free by never putting it in any public place, entering it into any forms, or sharing it with anyone I didn't actually want to talk to. For me, this has been blissful. Generally, when I receive email, its actual communication with a person I genuinely want to talk to, and I enjoy reading email.

A few years ago, my email bliss ended abruptly.

Spam? You May Rely on It

At my previous employer, I was forced to use Microsoft Outlook for my work-related email. From day one, I received hundreds of spam messages a day at my work email account. The Exchange server died routinely, leaving me without access to important communication. When I sent email, sometimes it just wouldn't be delivered, silently failing.

One day, in a moment of weakness, wanting to send a link home to myself so I could remember to read it later, I opened Outlook, pasted the link into a new message, and emailed it to my personal email address. The moment I pressed "Send", I knew I had made a mistake. But there was no going back. It was too late. My email address now lived in the Exchange Server.

The next day, spam started trickling in. A few days later, the trickling turned into gushing. As of last week, I was receiving 50 or 60 emails in my inbox a day that Spamassassin wasn't catching. My bliss had ended, and the era of spam had begun.

That is, until yesterday.

Outlook Not So Good

In a bout of frustration, I started looking at the headers of all the spam that was getting through my server-side filter to see what the spam scores were. Many of them were "close" to being marked as spam, but even more of them passed completely through. One thing I immediately noticed, though, was that all of the emails he had a specific header, with the same value, every time. Last night, I added the following rule to my procmail configuration, out of curiousity:

:0:
* ^X-Mailer:.*Microsoft.*
$DEFAULT/.Spam.Outlook/

This morning, my inbox had three new emails from friends, family, or acquaintances. My "Outlook Spam" folder had 87 new messages, all of which were spam. For the first time in over a year and a half, I had no spam slip through the cracks.

I am sure some of you will point out, now any email that I receive from people who use Outlook will end up being flagged as spam. Fair enough, but do I actually want to talk to those people? My magic 8 ball says: "Very doubtful."

Saved by Outlook. Sweet, sweet irony. Good riddance, spam.