Managing IMAP

To Filter or Not to Filter...

It’s clear that Procmail and Sieve have two slightly different aims. Procmail is flexible enough to be used for everything from a self-modifying reactive SPAM filter to a file server, while Sieve would offer the power of server-side filtration with the mechanical ease of client-side filtering. One issue should be covered, though. That issue is whether filtering should be done at all.

There is a handful of ethical and legal gotchas involved in doing server-side filtering, especially if the filtering is managed by the service provider and not the end user. We’ll leave you to sort out the various legal issues, but here are a few issues that merit consideration before you launch into providing filtering services.

Silencing the Bullhorn

Most enterprise-wide email systems have a mechanism for sending out broadcast messages to everyone in the organization. Unfortunately, these mechanisms are frequently used for trite “anyone want to buy my Beanie Baby” messages and, likewise, for firestorms of responses about such inane messages (and counter-firestorms to those responses). Ultimately, such threads serve to introduce many of the recipients to the capabilities of their MUA’s client-side filtering. The obvious problem here is that broadcast messages like “There’s a large noxious cloud of Benzene descending on campus” won’t reach the entire audience.

Actually, for installations that can’t or won’t control access to such broadcast mechanisms, ...