Why too aggressive an antispam filter is bad for you

There probably aren't many people on this planet that would love their daily dose of junk e-mail, although one can just wonder the creativity and efforts of the spammers.

Now, most everybody has somekind of spam filter in place. But, some people seem to take spam personally, and install an automatic filter that block incoming e-mail at the gateway/mail server. Yeah, that's cool technology, but when you turn the volume up and let the script kiddies (sorry) do the tweaking, that filter can literally kill your business.

I'd love to write a whole article about such bad filtering methods or the disastrous results, but it is enough to say that think twice before you install such a filter, and most importantly, do know how it works. In business, it is very scary to block e-mails based on reverse DNS rules, certain keywords, or mail header fields to name a few. Sure, no spam will get through, but at the same time, you will stop those orders coming in from customers or important mails from partners. Don't ask me how many time I've seen this happen in real life. Call this my anti-antispam quest, but watch out those free (Linux-based) "100% effective" filters. You've been warned.