Samba 4.0.0alpha1 [Released]

“Samba 4 is the ambitious next version of the Samba suite that
is being developed in parallel to the stable 3.0 series. The main
emphasis in this branch is support for the Active Directory logon
protocols used by Windows 2000 and above.

“Samba 4 is currently not yet in a state where it is usable in
production environments…”