Trials and Travails of Email Filtering

Not counting our managed servers or VPS plans, Modwest handles close to a million messages a day. And mailbox owners (including me!) reasonably want 2 things:

1. Keep junk and malware out of my inbox.
2. Give me all my legitimate mail.

Turns out it's really difficult to meet both goals 100% of the time. We could maybe guarantee #2 alone by delivering absolutely everything, but with 87% of email traffic consisting of junk mail, that solution probably wouldn't be appreciated by most!

So we do our best to filter out only the bad stuff that nobody wants. There are a lot of ways to try and do this, each layer of effort knocking out another portion of junk mail. (We describe some of these measures in our Knowledge Base here.)

We also provide a fair bit of control over how each mailbox handles spam within OnSite -- that's a goal of ours, to put maximum feasible control over spam handling to each mailbox owner, and we've got some additional control features planned. (The importance of recipient control over filtering was explored in a controversial article by the Electronic Frontier Foundation.)

Microsoft says that certain file attachment types are "high risk", and we know that certain filenames are associated with particular viruses and phishing attempts. Most would agree that we should try and prevent these potentially malicious attachments from being delivered.

We expend a fair bit of human time and CPU cycles trying to ensure both delivery goals mentioned are achieved. And yet the system's imperfect -- we regularly hear from customers who receive too much spam, or (infrequently) had a legitimate mail blocked or flagged as spam. It's a hard problem, but one we're committed to continuously improving.

All this leads one to wonder: Is email dead?

What do you think? What additional spam controls or filtering improvements would you like to see at Modwest?

-JM