Recent analyst estimates indicate that over 60 percent of the world's email is unsolicited email, or "spam."

Spam is no longer just a simple annoyance. Spam has now become a significant security issue and a massive drain on financial resources. In fact, this deluge of spam costs company's an estimated $20 billion each year in lost productivity.

Today there are a large number of solutions designed to help eliminate the spam problem. These solutions use different techniques for analyzing email and determining if it is indeed spam. Because spam is constantly changing, the most effective spam blocking solutions contain more than one of these techniques to help ensure that all spam, and only spam, is blocked. The following is an overview of different spam blocking techniques.

Below is some of our resources that we use...

  • Word Filters
  • Rule-based Scoring Systems
  • Bayesian Filters
  • Black List IP
  • RBL's (Realtime Blackhole Lists)
  • DNS MX Record Lookup
  • Reverse DNS Lookups
  • New Reverse Lookup Systems
  • Black List Sender Email Addresses
  • Honeypots (Hashing Systems, Fingerprinting)
  • Challenge/Response systems
  • Computational Challenge Systems
  • Rate Controls
  • Anti-Virus Scanning


Spam is a problem that is continuing to grow from day to day, costing company's billions of dollars in lost productivity. Fortunately though, there are different spam blocking techniques to help counter the various types of spam.

Because spammers are always trying to bypass anti-spam techniques by changing the methods they use to send spam, it's best for company's to protect themselves with a spam blocking solution that uses more than one spam blocking technique.Each one of these techniques has advantages, disadvantages, as well as limitations.

To minimize the amount of spam that enters an organization, a spam blocking solution that includes a combination of the most effective techniques should be implemented.