Perils of Filtering Server Side

Server side spam filtering has its place - but it also has problems.

Too frequently ISPs rate their spam solutions strictly on the grounds of how much email they block. The more bounced messages the better. This keeps the load on their servers low, and users don't complain about their spam problems.

What the users frequently can't complain about is the mail they missed. That's because they never find out about it. Most server-side anti spam programs don't have any mechanism to notify individual users what emails have been blocked.

A company I work with had their ISP repeatedly block e-mails from clients with messages like "601 Denied - Go Away Spammer!" This may have cost the company one client, and possibly others.

In contrast, PC-side solutions usually give users a way to review blocked messages, and decide if they want them restored. Problem email addresses can be white-listed so they aren't blocked again. Users can also create custom "good phrases" to make sure things like automated auction notices get delivered.

Where server-side filtering is handy is blocking the stuff you really know you don't want. Many server based systems do let you adjust the filters to make them perform conservatively. While this misses a portion of spam, it can still weed out some of the easy stuff with low risk of false positives.

SpamButcher is a next generation program that can stop spam in Outlook and most other email clients. Its 21-day trial download is available from this site.

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