As companies try to implement more security around their perimeters, an increasing number are turning to outsourcing to get the extra work done.

By 2005, 60 percent of enterprises will outsource monitoring of at least one perimeter security technology, according to a new report from Gartner, Inc., a major industry analyst firm.

Managed security services are relatively new to the marketplace, report Gartner analysts. But during the past two years, a significant expansion has occurred in the number of vendors and the range of managed-service offerings.

''Target customers include those enterprises without core competencies in information security,'' says Richard Hunter, vice president for Gartner. ''Such enterprises have addressed perimeter security and gained experience in putting their security architectures in place, and they are looking for efficient operations, but not at the expense of their security postures.''

E-commerce and business-to-business efforts are making security more difficult to manage.

Gartner's report notes that many companies are focusing on securing their perimeters -- keeping the bad guys out. But with the increasing role of e-commerce and business-to-business ventures in the corporate portfolio, IT managers also need to make sure the good guys can get in.

''Most enterprises will not have the resources to do an effective job at keeping the bad guys out and letting the good guys in,'' says Victor Wheatman, managing vice president for Gartner. ''Outsourcing keeping-the-bad-guys-out effort is a driver for the managed-security market. Enterprises should evaluate managed security services providers that have approximately 50 professional service professionals because those companies will likely become the enterprise's security provider.''