Why a whitelist?
We studied all the different methods for blocking spam and weighed the pros and cons of each. We found that the whitelist method had the most benefits with the fewest drawbacks. Our research included real world experience and looking into various studies regarding anti-spam techniques. Blacklists and content/heuristic filters, two of the more popular anti-spam methods, are inherently unable to block all of the spam coming into an organization. The various filter methods also require frequent adjustment and have unacceptable rates of false-positives (i.e. legitimate mail flagged as spam). With our whitelist implementation, you get near 100% block rates with virtually no “false positive” issues.
