Microsoft\u00a0Monday added yet another anti-spam technology to its recently released Exchange Server 2003 that it said would give companies another level of protection as they battle the onslaught of junk e-mail.Microsoft, however, said its Intelligent Message Filter (IMF), which is slated for release in the first half of 2004, does not signal that the software giant plans to become an anti-spam vendor.\u201cThis is unlikely to be a primary line of defense,\u201d says a T.A. McCann, group product manager for Exchange. \u201cWe think it will do a reasonably good job of filtering but doesn\u2019t have all the features. We are augmenting what we did in Exchange 2003.\u201dHe said IMF could help companies build a multi-tier approach to battling spam that would include a third-party filter at the gateway and at the server inside a firewall.Spam has grown into a menace over the past few years for enterprise e-mail users. Anti-spam vendor Brightmail says spam accounted for 54% of Internet mail traffic in October, up from 40% just 12 months earlier.IMF is based on Microsoft\u2019s SmartScreen Technology, which was developed by Microsoft Research and learns to recognize what is and isn\u2019t spam using a series of probability-based algorithms. The software adapts over time and Microsoft said it would provide regular updates to the filter. The technology is already available in Outlook 2003, MSN8 and Hotmail.\u00a0Experts say that while Microsoft is adopting a complementary role in the fight against spam the company should be doing more.\u201cWhat they are doing is pretty minimal, but we are glad to see them take this step,\u201d says Chris Williams, an analyst with Ferris Research. \u201cI hope they eventually pour more resources into fighting the problem.\u201dExchange 2003, which shipped in October, features a handful of anti-spam capabilities including support for safe sender and block lists, global reject-and-accept lists, and sender and recipient filtering. An updated virus-scanning API was added to better integrate with third-party tools. Microsoft also introduced technology called Spam Confidence Level (SCL) that allows third-party filters that support SCL to assign a rating to each message grading its probability of being spam. Exchange Server 2003 includes controls for filtering messages based on those scores.Ferris\u2019 Williams says Microsoft needs to go further and allow user-based management of filtering at the server and to allow users to check for quarantined mail.Microsoft\u2019s McCann said how the end user helps train filters to recognize spam is important to Microsoft\u2019s future strategy, but that those capabilities won\u2019t be put into Exchange or Outlook in the near future.IMF uses information gleaned from its Hotmail users to catalog 500,000 characteristics of spam that SmartScreen Technology can track.IMF uses those characteristics to help administrators tune the IMF filter using the standard Exchange management tools.