New Version of Quest's Vintela Authentication Services Now Available.

Founding Member of Microsoft's Interop Vendor Alliance Also Introduces New Online Community Dedicated to Heterogeneous Integration

LAS VEGAS -- Quest Software, Inc. (Nasdaq:QSFT), a founding member of Microsoft's Interop Vendor Alliance, today announced general availability of the newest version of its solution for extending Active Directory-based authentication and single sign-on across heterogeneous systems. At the same time, Quest unveiled a new online community, "Inside Vintela," that provides user interaction, online support and product information, tips and resources to IT professionals using Quest solutions to enhance heterogeneous systems integration within their organizations.

"We are very glad that Quest accepted our invitation to participate in the Interop Vendor Alliance, as their innovative work in heterogeneous integration brings value to our mutual customers," said Sam Rosenbalm, business development manager, developer and platform strategy group at Microsoft. "Quest's software and expertise can help our customers move along the continuum toward unified systems management across platforms."

"Microsoft technologies are the foundation for business computing at many organizations around the world, but as we know, most of these enterprises are also heterogeneous," said Dave Wilson, vice president, Vintela products, Quest Software. "The ability to extend the powerful capabilities of Microsoft technologies to non-Microsoft platforms is key to success for these organizations.

"Microsoft has purposefully chosen to base its solutions Co such as Active Directory, SMS and MOM Co on established industry standards," Wilson continued. "This approach creates an ideal platform upon which to build a unified management infrastructure for the heterogeneous enterprise. Quest provides the enabling technologies that allow organizations to get the most from their investment in Microsoft infrastructure by extending the reach of those capabilities across platforms. We're very pleased to be among the founding members of the Interop Alliance."

Introduced in October, version 3.1 of Quest's Vintela Authentication Services is now generally available. The product enables step-by-step progress toward a single, unified Active Directory-based identity infrastructure that encompasses Unix and Linux systems, users, and applications. Administrators who choose complete migration of Unix identities to Active Directory will benefit from the product's new wizard for a structured, automated and manageable migration.

The new development community site, Inside Vintela (http://vintela.inside.quest.com), is designed to provide an open forum for prospects and customers of Quest's heterogeneous integration software products to share best practices, experiences and ideas with their peers. The community also supports interaction with experts from the Quest product management and development teams as well as allowing members to benefit from open communications with other users of Quest's cross-platform integration products.

Quest products highlighted within the Inside Vintela community include:

* Vintela Authentication Services - allows customers to seamlessly extend the security and compliance of the Microsoft Active Directory infrastructure to Unix and Linux platforms and applications.

* Vintela Single Sign-on for Java - leverages the existing Kerberos support in Active Directory to provide a comprehensive, cross-platform single sign-on solution for J2EE.

* Quest Management Xtensions for SMS - natively extends the change and configuration capabilities of Microsoft Systems Management Server (SMS) 2003 to Unix, Linux and Mac OS X systems.

* Quest Management Xtensions for MOM - natively extends the operations and event management capabilities of Microsoft Operations Manager (MOM) 2005 to Unix and Linux systems - including Management Pack authoring capabilities.

The community also includes Resource Central, a collection of software and documentation projects that allow Quest customers to use popular open-source software solutions in conjunction with Quest's commercial Vintela products and support. Resource Central is operated as a collection of true open-source projects, with patches and documentation available in source code form.

About the Interop Vendor Alliance

Formed in 2006, the Interop Vendor Alliance is an industrywide group working to identify and share opportunities to better connect people, data and diverse systems through better interoperability with Microsoft systems and to jointly market interoperability solutions of its members. Founding members include AMD, BEA Systems, Business Objects, CA, The Carbon Project, Centeris, Citrix Systems, GXS, IP Commerce, JNBridge, Kernel Networks, Levi, Ray & Shoup, Microsoft, NEC, Network Appliance, Novell, Q4bis, Quest Software, Siemens Enterprise Communications, SOFTWARE AG, SugarCRM, Sun Microsystems, Symphony Services, Xcalia, and XenSource. Additional information about the Interop Vendor Alliance can be found on its Web site at http://www.interopvendoralliance.org.

About Quest Software, Inc.

Quest Software, Inc. delivers innovative products that help organizations get more performance and productivity from their applications, databases and Windows infrastructure. Through a deep expertise in IT operations and a continued focus on what works best, Quest helps thousands of customers worldwide meet higher expectations for enterprise IT. Quest's Windows Management solutions simplify, automate and secure Active Directory, Exchange and Windows, as well as integrate Unix, Linux and Java into the managed environment. Quest Software can be found in offices around the globe and at www.quest.com.

Quest and Quest Software are registered trademarks of Quest Software, Inc. The Quest Software logo and all other Quest Software product or service names and slogans are registered trademarks or trademarks of Quest Software, Inc. All other trademarks and registered trademarks are property of their respective owners.

Forward-Looking Statements

This release may include predictions, estimates and other information that might be considered forward-looking statements, including statements concerning the availability and market acceptance of our new version of Vintela Authentication Services. These statements are based on current expectations and assumptions that are subject to risks and uncertainties. Actual results could differ from those anticipated as a result of various factors, including: the impact of adverse changes in general economic conditions on our relationships with customers, strategic partners and vendors; reductions or delays in information technology spending; variations in demand or the size and timing of customer orders; competitive conditions in our various product areas; rapid technological change; risks associated with the development and market acceptance of new products and product strategies; disruptions caused by acquisitions of companies and/or technologies; fluctuating currency exchange rates and risks associated with international operations; the need to attract and retain qualified employees; and other risks inherent in software businesses. For a discussion of these and other related risks, please refer to our recent SEC filings, including our Annual Report on Form 10-K for the year ended December 31, 2005. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date thereof. We undertake no obligation to update forward-looking statements to reflect events or circumstances after the date thereof.