Microsoft Corp. said Wednesday that it is buying e-mail security vendor FrontBridge Technologies Inc., which provides managed e-mail antispam, antivirus, disaster continuity and archiving services. The deal, announced late this afternoon, is aimed at giving Microsoft more features to offer Exchange Server customers with growing messaging requirements.

The price tag for the purchase was not disclosed. The deal is expected to be finalized by September, pending regulatory approvals, according to Kim Akers, general manager of Exchange Server marketing.

The acquisition was prompted by Exchange customers, who have been asking for additional features to streamline and simplify their messaging infrastructures, Akers said.

Dave Cohen, vice president and co-founder of Los Angeles-based FrontBridge, said his company"s managed messaging services for competing software, including IBM"s Lotus Notes, will continue to be developed and offered after the acquisition. "Microsoft has committed to move along our business model to ensure that customers have the same services today and tomorrow," he said. "From our perspective, we have a very defined shared vision and go-to-market strategy."

The company"s 160 global employees will remain with the company after the purchase, he said.

FrontBridge provides managed e-mail services that clean messages for customers before viruses and spam can get into in-boxes. The company also offers archiving, compliance and e-mail continuity services in the event of disasters that can knock e-mail systems out of operation.

Analyst Matt Cain at Gartner Inc. said the acquisition "presents a very intriguing business opportunity" for Microsoft as it works to build up its portfolio of Exchange services. "This model for e-mail hygiene is growing in popularity," Cain said. "Companies don"t want to dedicate their IT teams" to manage spam, antivirus and other protection layers, and are turning more and more to bringing in a vendor to do it for them.

IDC analyst Robert Mahowald said that since customers are seeking such services elsewhere, Microsoft might as well offer them.

"It makes more sense to buy [such a company] rather than build a technology for themselves," Mahowald said. Many Exchange customers are already using managed services from FrontBridge, he said. "Microsoft saw a need here that was worth getting into."