The team behind the Samba Project has released version 4.0 of its open source Windows interoperability software suite, the first version to offer full compatibility with Microsoft's Active Directory protocols.

The Samba stack is by far the most popular solution for networking non-Microsoft platforms with Windows machines, but previous versions only provided Windows NT Domain Controller functionality.

According to the Samba Team's press release, Samba 4 can now act as an Active Directory Domain Controller and offer services to any currently supported versions of client-side Windows, including Windows 8.

Servers running the new Samba support typical Active Directory features, including Group Policy and Roaming Profiles. They can also integrate with Microsoft Exchange servers, and they can even be managed using Microsoft's own administration tools.

In addition, the new version offers full interoperability with Microsoft Active Directory servers. A Samba 4 server can be joined to an existing Active Directory domain, and Microsoft Active Directory Domain Controllers can join a Samba 4 server.

What all of this means is that for the first time, organizations have the option of replacing one or more Microsoft Active Directory servers – currently priced starting at $501 apiece for the small business version and scaling up to the Moon – with alternatives based on 100 per cent free software, via Samba 4.0 running on Linux or some other free OS.

If Microsoft is upset about that, though, it's not letting on. In fact, Redmond provided the Samba team with the official documentation for the Active Directory protocols, in addition to giving it access to Microsoft's own interoperability labs to ensure that Samba's implementation was fully compatible with Microsoft's.

"We are pleased that the documentation and interoperability labs that Microsoft has provided have been key in the development of the Samba 4 Active Directory functionality," Thomas Pfenning, Microsoft's director of Windows Server development, said in a statement.

But "pleased" may actually be too strong a word, since Redmond didn't exactly volunteer to help the Samba Team.

The collaboration between Microsoft and Samba stems from a hard-won legal agreement inked in December 2007, in which Samba paid a one-time fee of €10,000 in exchange for information about Microsoft's protocols and a royalty-free license to use them.

That agreement only came after the European Commission ordered Microsoft to disclose technical information about Windows to its rivals, as a result of an anti-trust ruling against the company in 2004.

Willing or not, however, the partnership seems to have borne fruit for the Samba Project, which describes Samba 4.0 as "the culmination of ten years' work."

In addition to the Active Directory functionality, Samba 4 includes new support for version 2.1 of Microsoft's Server Message Block (SMB) file serving protocol, with preliminary support for version 3. It also adds the capability to act as a clustered file server, offering a "single server" view of clustered file storage.

The Samba 4.0 source code is available for download now from the project's website, with binary packages expected to arrive soon from a variety of sources. The stack is free software distributed on the GNU General Public License, Version 3.

More information on the new features and changes included in Samba 4 is available the official release notes. ®