Server Message Block

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Server Message Block

(SMB) A client/server protocol that provides file and printer sharing between computers. In addition SMB can share serial ports and communications abstractions such as named pipes and mail slots. SMB is similar to remote procedure call (RPC) specialised for file system access.

SMB was developed by Intel, Microsoft, and IBM in the early 1980s. It has also had input from Xerox and 3Com. It is the native method of file and print sharing for Microsoft operating systems; where it is called Microsoft Networking. Windows for Workgroups, Windows 95, and Windows NT all include SMB clients and servers. SMB is also used by OS/2, Lan Manager and Banyan Vines. There are SMB servers and clients for Unix, for example Samba and smbclient.

SMB is a presentation layer protocol structured as a large set of commands (Server Message Blocks). There are commands to support file sharing, printer sharing, user authentication, resource browsing, and other miscellaneous functions. As clients and servers may implement different versions ("dialects") of the protocol they negotiate before starting a session.

The redirector packages SMB requests into a network control block (NBC) structure that can be sent across the network to a remote device.

SMB originally ran on top of the lower level protocols NetBEUI and NetBIOS, but now typically runs over TCP/IP.

Microsoft have developed an extended version of SMB for the Internet, the Common Internet File System (CIFS), which in most cases replaces SMB. CIFS runs only runs over TCP/IP.

Just what is SMB?.

IBM protocols.

Microsoft SMB/CIFS documents.
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(1) (Small to Medium-sized Business) Also called small to medium-sized enterprise (SME), SMBs are companies with approximately 25 to 500 employees. However, some SMB/SME ranges use an upper limit of 5,000. From an IT viewpoint, SMB/SME designations mean the number of workstations that must be managed. See SOHO.

(2) (Server Message Block) The file sharing protocol in DOS and Windows. In the 1990s, Microsoft renamed SMB to "Common Internet File System" (CIFS), and it is often referred to as SMB/CIFS. Mac and Linux computers also use SMB/CIFS to access shared folders on Windows machines and vice versa.

SMB originated with the NetBIOS protocol used in the first DOS networks and later migrated to OS/2 and Windows. See CIFS, file sharing protocol and Samba.

SMB Means Network Shares
In mixed-platform networks, users may run across the term SMB. This example is the file manager from the KDE user interface on a Linux computer. The "SMB Shares" icon represents all the shared files and folders on the Windows computers in the network.

From Mac to Windows
This Mac dialog was displayed when trying to connect from the Mac to a Windows machine on the network. The SMB/CIFS nomenclature was later dropped in Mac OS X 10.5 (Leopard) to hide the jargon.
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initiated through a Server Message Block version 2 (SMBv2)
[2] CIFS and SMB: CIFS stands for Common Internet File System; SMB stands for Server Message Block. Both are widely used communications protocols for file sharing.
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