January 23, 2013, 10:55 AM — Samba 4.0 is a milestone release that brings Active Directory functionality to the open source SMB/CIFS (Server Message Block/Common Internet File System) file and print server. Samba 4.0 can serve as an Active Directory Domain Controller, provide DNS services, handle Kerberos-based authentication, and administer group policy. The Samba 4.0 Domain Controller can even be managed using the native Windows Active Directory admin tools.
However, there are restrictions in this release -- mainly issues with file replication -- that limit the number of Domain Controllers you can join to only a single domain. Support for cross-forest trusts and multiple domain controllers is still to come. When that support arrives, Samba will be truly useful as an Active Directory replacement. Until then, the Domain Controller functionality is suitable mainly for testing. Not many environments can make good use of a single domain controller.
Beyond file and print servicesSMB is the protocol behind all network file communication used natively by Windows Server and Windows clients; it's also known as CIFS. Support for SMB/CIFS on other operating systems has primarily come from the Samba project. Samba started back in 1992 as a way to connect Unix and Linux machines to Microsoft's LAN Manager network operating system. It's provided the plumbing necessary for Unix and Linux machines to connect to Microsoft networks ever since.
The most common use of Samba is still in the client role, but that has changed along the way with the ability to provide file and print services to Unix and Linux clients, as well as systems running various versions of Windows.