Microsoft is to build anti-spam technology into Exchange Server from the middle of next year, prompting resellers of third-party software to predict benefits for the whole market.
The server module, called Microsoft Exchange Intelligent Message Filter, is similar to the anti-spam technology already built into Outlook 2003 and Hotmail.
The technology uses a scanner which identifies spam by its content and by its behaviour on the network. The spam filter will be updated monthly from lists sent in by Hotmail users.
Microsoft Exchange Intelligent Message Filter is designed to work with other third-party anti-spam products and has been back by market players such as Brightmail.
Ross McWilliam, managing director of reseller Zen Software, said Microsoft's moves could actually expand the market.
"This can be a positive thing. The fact Microsoft is coming into the market shows how serious the problem is," he said.
"Companies that have been putting off buying an anti-spam solution will now be pushed to look at the options."
But Graham Cluley, senior technology consultant at antivirus and anti-spam vendor Sophos, questioned whether putting anti-spam sofware on the server was the right approach. "Our resellers tell us large companies don't want this and it may not work," he said.
"Exchange doesn't have the infrastructure to stop spam effectively for them. The job needs to be done closer to the internet access point, before it gets into the organisation. Deciding to update spam definitions on a monthly basis is also too slow for serious anti-spam filters."
This is not the first time Microsoft has tried incorporating anti-spam technology. In 1999 it introduced SmartScreen to check for spam in users' Hotmail accounts.
Initially the results were very positive, but spammers soon learned how to bypass the controls.
Microsoft is also working on other anti-spam technology, including developing a 'Trusted Sender' programme with AOL, Yahoo and Earthlink, and donating lobbying time and funding for anti-spam legislation in the US.
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