The Antigen products are part of a continuing effort by Microsoft to expand its portfolio of security offerings for both corporate users and consumers. That effort has included several acquisitions in recent years, such as antivirus software makers GeCAD Software and Giant Company Software Inc., ID management vendor Alacris Inc., and SSL virtual private network vendor Whale Communications Inc.

Despite those efforts, some users say they still need to be convinced that Microsoft can be a strong supplier of security tools.

"I definitely want to see one or two versions of their products come out" before implementing them, Alex Schjelde, manager of information security at CenturyTel Inc. in Monroe, La., said at Gartner Inc.'s IT Security Summit in Washington last week. "I don't think I'm prepared to be among the first ones to try them out."

Sven Doersam, desktop security lead at Johns Hopkins University, said at the Gartner conference that he plans to evaluate the tools after other sites gain experience with them. "We are going to wait and see" how the products evolve before deciding whether to implement them, he said.

The updated products unveiled last week include Antigen for Exchange, Antigen for SMTP Gateways, Antigen Spam Manager, Antigen Enterprise Manager and the Antigen Messaging Security Suite, which combines antivirus, antispam and content filtering for Exchange Server 2003 and Exchange 2000 e-mail servers and SMTP gateways.