Management vendor Quest Software on Tuesday said it would spend $56.5 million in cash to acquire privately held Vintela, which develops software to integrate Microsoft management tools with other platforms.

The acquisition brings together two companies focused on managing and extending Windows resources, most notably Active Directory. Quest, which develops application, database and Windows management software, plans to use Vintela’s integration technology to push itself into the identity management arena including providing support for cross-platform user provisioning, password management and end-user self-service applications.

Quest says its long-term strategy is to extend Active Directory so companies can use it to manage and secure their Unix, Linux, Macintosh and Java platforms.

“When you start trying to scale the Microsoft environment to a very large enterprise and deal with the management issues around hundreds of servers and tens of thousands of desktops it overwhelms some of the pieces you get out of the box with Microsoft. At that point you need third-party products,” says Phil Schacter, vice president and research director with the Burton Group.

Schacter says the marriage of Quest and Vintela could become a good one for IT executives. “If they are a large Windows shop there is a likelihood they are already Quest customers. Now they have a better approach on how to do things such as single sign-on from a Unix environment leveraging Active Directory. It is one more tool that helps solve some sub-set of the day-to-day interoperability problems without having to deal with another small vendor.”

Quest, which is based in Irvine, Calif., has been acquiring companies over the past few years to build its management and Active Directory business, including Fastlane Technologies in 2000 for its directory management tools, and Aelita in 2004 for its directory and Exchange management software.

Vintela, which is based in Lindon, Utah, has been rising on the radar screen lately with a set of tools for integrating non-Windows platforms with Active Directory, Microsoft Operations Manager (MOM) and System Management Server (SMS). The tools include Vintela Authentication Services for cross-platform identity management; Single Sign-on for Java, which integrates J2EE environments with Active Directory; Group Policy, which extends that Active Directory desktop and server management feature to Unix and Linux; and Management Extensions, which extends SMS to Unix, Linux and Macintosh-based systems.