IT managers should rethink their spam filter strategy as the market is expected to experience dramatic vendor consolidation this year, Gartner has warned.

According to the analyst group, fewer than 10 of the 40 vendors in the market will still be in business by 2005.

And current firewall, antivirus and web filtering vendor technology fails to meet enterprise requirements, while companies that do offer viable products are smaller and have a limited track record.

Enterprises need sophisticated detection engines that are constantly updated, said Arabella Hallawell, research director at Gartner, in a statement.

"If a solution blocks legitimate business email, or is too restrictive or inflexible for an enterprise culture, it's not viable," she said.

"If the spam filtering solution requires a team of administrators or heavy end user involvement to administer and update, then it's not practical either."

Before signing contracts with suppliers, enterprises should request protection clauses to cover them in the event of a vendor being acquired, and should also demand shorter-term contracts.

"Companies must consider a vendor's core business fundamentals. A quality installed base also indicates sufficient strength to mitigate short-term vendor risks," added Hallawell.

Maurene Caplan Grey, research director at Gartner, added that enterprises cannot afford to delay decisions until the market shakes out.

"Their problems with spam have become too enormous," she said.

Gartner said 60 per cent to 75 per cent of the incoming email received by its clients is spam.