To be exact, "Samba 4.1.0 contains the first release of our client tools and client library that work over the new protocols SMB2 or SMB3." That said, "The default protocol for smbclient and smbcacls is still SMB1 (the NT1 protocol dialect). If you want to use the newer versions of SMB you'll need to set them up manually by adding the -mMAX_PROTOCOL command line switch to either smbclient or smbcacls."
An easier way to do this will be to use the "client max protocol" parameter in the [global] section of your Linux desktop's or Mac's smb.conf file. For example, by placing
client max protocol = SMB3
in the smb.conf file these desktops will automatically try the SMB3 protocol when connecting to Windows 8, Windows 2012, or Samba 4.x server. Eventually this will also enable Macs, which can also use Samba, to connect to these file servers as well.
While this nuts and bolts approach won't appeal to anyone except system administrators, GUI-based file sharing tools will hide these technical details away as Samba 4.1 is integrated into desktops.
One tool you won't be able to use on Linux to set up your desktop to use SMB3 is the venerable Samba Web Administration Tool (SWAT). SWAT has been swatted not because the tool isn't useful, but it's proven beyond the Samba project's resources to properly secure it. So, rather than expose file sharing to possible attacks via SWAT, the program been placed into retirement.
Jeremy Allison, a senior Samba developer and Google's Linux evangelist added that, "With theit's nice to note we now support SMB3 transport level encryption to Windows 2012 servers as well as Samba4 servers. We've had Samba -> Samba transport encryption over SMB1 for many years already, of course, having it [transport encryption] to Windows servers is the new thing." This means that Linux systems sharing files from Server 2012 will be far less prone to having the file's data snatched in mid-stream.
"Although," Allison wryly noted, "With the design of that protocol coming from a US-based company it's hard to know if it's completely trustworthy."
In addition this new Samba brings improved directory database replication and server-side copy. Finally, Samba brings better Linux btrfs support, and, as Allison noted, "A boatload of fixes and stabilization as we push towards full SMB3 support!"