Server Message Block

Server Message Block ( SMB short, partly as a LAN Manager or NetBIOS protocol known) is a communications protocol for file, print, and other server services in networks. It is the core of the network services of Microsoft's LAN Manager, the Windows product family as well as the LAN server from IBM. Further, it is used by the freely available software projects Samba and Samba -TNG to allow Windows systems to access resources of Unix -based systems and vice versa.

SMB implements a network file system like NFS and is thus on the underlying file system of the server largely independent.

In TCP / IP networks SMB was originally encapsulated in NetBIOS over TCP / IP ( NBT) over the TCP / UDP ports 137-139, the name resolution has often using WINS or broadcasts. Newer versions of Windows run SMB directly on TCP port 445 and resolve names via DNS and small networks by LLMNR on.

Common Internet File System ( CIFS)

The term Common Internet File System ( CIFS short ) was introduced in 1996 by Microsoft and describes an enhanced version of SMB. CIFS builds on NetBIOS over TCP / IP and SMB and offers both file and printer sharing other services such as the Windows RPC and the NT domain service to. Name resolution is done while still on NBT broadcasts or generally speaking the NBT name service or DNS if NBT is not available.


SMB was first introduced in 1983 by Barry Feigenbaum at IBM. Over time the protocol by different companies and groups, including Microsoft, SCO, Thursby, IBM and the Samba Team has been expanded. Microsoft contributed the most extensions, but only since 2007 released under pressure from the European Union, their full description.

In Windows Vista / Windows Server 2008, a proprietary new version of the protocol was introduced with SMB 2.0, the specification of which, however, is open. The free SMB implementation Samba since version 3.5 supports this new protocol version. With Windows 7 / Windows Server 2008 R2 SMB 2.1 was introduced in Windows 8 / Windows Server 2012 includes SMB 3.0.