SMB (Server Message Block) is an application protocol, most commonly used for file and printer sharing. Although it was originally designed by IBM for use in OS/2, it has been adopted and improved upon by Microsoft as the primary protocol for file and printer sharing in their Windows for Workgroup. It has been in use ever since on Windows and a myriad of other OS flavours.

Although SMB is proprietary to Microsoft, SMB is also available on linux (through Samba), Apple (first Samba, then later, Apple's own SMBX), and a myriad of other OS vendors. In fact, Apple has replaced their own AFP in favour of SMB in their latest releases of Mac OSX. SMB has become the most commonly used protocol for file and print sharing in a LAN, regardless of the OS used.

Over the years, Microsoft has added additional functionality and performance to SMB. Although backwards compatible, the changes between versions are significant. Therefore, it is useful to know which versions of SMB are supported by which OS. This article contains a list of OSes and the SMB versions they support.

More information on SMB and its history available on Wikipedia: http://en.wikipedia.org/wiki/Server_Message_Block

SMB version reference table

Some remarks

• For Windows, the highest supported version on the client and server is used: i.e. an XP machine connecting to a 2012 will use SMB 1.0 because the client only supports 1.0. Also, starting from Windows 8.1/2012R2, SMB 1.0 is disabled by default, so pre-Vista clients can only access shares on a 8.1/2012R2 if it is manually enabled.
• For linux and BSD-based systems, the supported SMB versions depend on the version of Samba installed.
• Mac OSX Lion (10.7) introduced support for SMB2 as Apple switched to their own implementation of SMB, but only since OSX Mavericks (10.9), it defaulted to version 2. Mac OSX Jaguar (10.2) was the first to introduce support for SMB. Before, only AFP was supported.
• SMB 1.0 is also referred to as CIFS.