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64-458: SMB3 may refer to: Server Message Block version 3, a network protocol in computing Super Mario Bros. 3 , a 1988 video game Super Mega Baseball 3, an entry in the Super Mega Baseball video game series [REDACTED] Topics referred to by the same term This disambiguation page lists articles associated with the same title formed as

128-580: A free-software re-implementation (using reverse engineering ) of the SMB/CIFS networking protocol for Unix-like systems, initially to implement an SMB server to allow PC clients running the DEC Pathworks client to access files on SunOS machines. Because of the importance of the SMB protocol in interacting with the widespread Microsoft Windows platform, Samba became a popular free software implementation of

192-410: A multiplexing service for multiple services or multiple communication sessions at one network address. In the client–server model of application architecture, multiple simultaneous communication sessions may be initiated for the same service. For TCP and UDP, a port number is a 16-bit unsigned integer, thus ranging from 0 to 65535. For TCP, port number 0 is reserved and cannot be used, while for UDP,

256-518: A URL like http://www.example.com:8080/path/ specifies that the web browser connects instead to port 8080 of the HTTP server. The concept of port numbers was established by the early developers of the ARPANET in informal cooperation of software authors and system administrators. The term port number was not yet in use. It was preceded by the use of the term socket number in the early development stages of

320-668: A compatible SMB client and server to allow non-Windows operating systems, such as Unix-like operating systems, to interoperate with Windows. As of version 3 (2003), Samba provides file and print services for Microsoft Windows clients and can integrate with a Windows NT 4.0 server domain, either as a Primary Domain Controller (PDC) or as a domain member. Samba4 installations can act as an Active Directory domain controller or member server, at Windows 2008 domain and forest functional levels. Package managers in Linux distributions can search for

384-516: A dedicated administrative function, which he called a czar , to maintain a registry. The 256 values of the AEN were divided into the following ranges: The Telnet service received the first official assignment of the value 1. In detail, the first set of assignments was: In the early ARPANET, the AEN was also called a socket name , and was used with the Initial Connection Protocol (ICP),

448-622: A lack of support for newer authentication protocols like NTLMv2 and Kerberos in favor of protocols like NTLMv1, LanMan , or plaintext passwords. Real-time attack tracking shows that SMB is one of the primary attack vectors for intrusion attempts, for example the 2014 Sony Pictures attack , and the WannaCry ransomware attack of 2017. In 2020, two SMB high-severity vulnerabilities were disclosed and dubbed as SMBGhost ( CVE-2020-0796 ) and SMBleed ( CVE-2020-1206 ), which when chained together can provide RCE (Remote Code Execution) privilege to

512-631: A large variety of SMB clients and servers. SMB1 features many versions of information for commands (selecting what structure to return for a particular request) because features such as Unicode support were retro-fitted at a later date. SMB2 involves significantly reduced compatibility-testing for implementers of the protocol. SMB2 code has considerably less complexity since far less variability exists (for example, non-Unicode code paths become redundant as SMB2 requires Unicode support). Apple migrated to SMB2 (from their own Apple Filing Protocol , now legacy) starting with OS X 10.9 "Mavericks" . This transition

576-488: A letter–number combination. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=SMB3&oldid=1174028655 " Category : Letter–number combination disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Server Message Block SMB

640-590: A list of hosts and their port numbers and the corresponding function used at each host in the network. This first registry function served primarily as documentation of usage and indicated that port number usage was conflicting between some hosts for "useful public services". The document promised a resolution of the conflicts based on a standard that Postel had published in May 1972 in RFC 349, in which he first proposed official assignments of port numbers to network services and suggested

704-419: A message. Specific port numbers are reserved to identify specific services so that an arriving packet can be easily forwarded to a running application. For this purpose, port numbers lower than 1024 identify the historically most commonly used services and are called the well-known port numbers . Higher-numbered ports are available for general use by applications and are known as ephemeral ports . Ports provide

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768-445: A multiprotocol, identity-aware platform for network access to files used in OEM storage products built on Linux/Unix based devices. The platform could be used for traditional NAS, Cloud Gateway, and Cloud Caching devices for providing secure access to files across a network. Likewise was purchased by EMC Isilon in 2012. KSMBD is an open source in-kernel CIFS/SMB server implementation for

832-479: A network with a smaller number of hosts, increased broadcast traffic can cause problems as the number of hosts on the network increases. The implementation of name resolution infrastructure in the form of Windows Internet Naming Service (WINS) or Domain Name System (DNS) resolves this problem. WINS was a proprietary implementation used with Windows NT 4.0 networks, but brought about its own issues and complexities in

896-469: A network. However the SMB itself does not use broadcasts—the broadcast problems commonly associated with SMB actually originate with the NetBIOS service location protocol. By default, a Microsoft Windows NT 4.0 server used NetBIOS to advertise and locate services. NetBIOS functions by broadcasting services available on a particular host at regular intervals. While this usually makes for an acceptable default in

960-443: A new opportunistic locking mechanism. SMB 3.0 (previously named SMB 2.2) was introduced with Windows 8 and Windows Server 2012 . It brought several significant changes that are intended to add functionality and improve SMB2 performance, notably in virtualized data centers : It also introduces several security enhancements, such as end-to-end encryption and a new AES based signing algorithm. SMB 3.0.2 (known as 3.02 at

1024-411: A secondary name resolution protocol for interoperability with legacy Windows environments and applications. Further, Microsoft DNS servers can forward name resolution requests to legacy WINS servers in order to support name resolution integration with legacy (pre-Windows 2000) environments that do not support DNS. Network designers have found that latency has a significant impact on the performance of

1088-422: A single request, which significantly reduces the number of round-trips the client needs to make to the server, improving performance as a result. SMB1 also has a compounding mechanism—known as AndX—to compound multiple actions, but Microsoft clients rarely use AndX. It also introduces the notion of "durable file handles": these allow a connection to an SMB server to survive brief network outages, as are typical in

1152-530: A transport (a largely experimental effort that required further refinement). Microsoft submitted some partial specifications as Internet Drafts to the IETF . These submissions have since expired. Microsoft introduced a new version of the protocol (SMB 2.0 or SMB2) in 2006 with Windows Vista and Windows Server 2008 . Although the protocol is proprietary, its specification has been published to allow other systems to interoperate with Microsoft operating systems that use

1216-438: A wireless network, without having to incur the overhead of re-negotiating a new session. SMB2 includes support for symbolic links . Other improvements include caching of file properties, improved message signing with HMAC SHA-256 hashing algorithm and better scalability by increasing the number of users, shares and open files per server among others. The SMB1 protocol uses 16-bit data sizes, which amongst other things, limits

1280-594: Is a family of portable SMB client and server implementations developed by Visuality Systems , an Israel-based company established in 1998 by Sam Widerman, formerly the CEO of Siemens Data Communications. The NQ family comprises an embedded SMB stack (written in C), a Pure Java SMB Client, and a storage SMB Server implementation. All solutions support the latest SMB 3.1.1 dialect. NQ for Linux , NQ for WinCE , iOS, Android, VxWorks and other real-time operating systems are all supported by

1344-445: Is a proprietary SMB server implementation developed by Tuxera that can be run either in kernel or user space . It supports SMB 3.1.1 and all previous versions, additionally advanced SMB features like continuous availability (persistent handles) scale-out, RDMA (SMB Direct), SMB multichannel, transparent compression, shadow copy . Likewise developed a CIFS/SMB implementation (versions 1.0, 2.0, 2.1 and NFS 3.0) in 2009 that provided

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1408-405: Is an extremely chatty protocol, which is not such an issue on a local area network (LAN) with low latency. It becomes very slow on wide area networks (WAN) as the back and forth handshake of the protocol magnifies the inherent high latency of such a network. Later versions of the protocol reduced the high number of handshake exchanges. One approach to mitigating the inefficiencies in the protocol

1472-654: Is for ephemeral ports . Transport-layer protocols , such as the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP), transfer data using protocol data units (PDUs). For TCP, the PDU is a segment , and for UDP it is a datagram . Both protocols use a header field for indicating the source and destination port numbers. The port numbers are encoded in the transport protocol packet header , and they can be readily interpreted not only by

1536-409: Is notable for its now-common scheme of representing symlinks. This "Minshall-French" format shows symlinks as textual files with a .symlink extension and a Xsym\n magic number, always 1067 bytes long. This format is also used for storing symlinks on native SMB servers or unsupported filesystems. Samba supports this format with an mfsymlink option. Docker on Windows also seems to use it. NQ

1600-1039: Is to use WAN optimization products such as those provided by Riverbed , Silver Peak , or Cisco . A better approach is to upgrade to a later version of SMB. This includes upgrading both NAS devices as well as Windows Server 2003. The most effective method to identify SMB1 traffic is with a network analyzer tool, such as Wireshark . Microsoft also provides an auditing tool in Windows Server 2016 to track down devices that use SMB1. Microsoft has marked SMB1 as deprecated in June 2013. Windows Server 2016 and Windows 10 version 1709 do not have SMB1 installed by default. In 1996, when Sun Microsystems announced WebNFS , Microsoft launched an initiative to rename SMB to Common Internet File System (CIFS) and added more features, including support for symbolic links , hard links , larger file sizes, and an initial attempt at supporting direct connections over TCP port 445 without requiring NetBIOS as

1664-634: Is used to transport email to and from other servers. This is accomplished with the Simple Mail Transfer Protocol (SMTP). A standard SMTP service application listens on TCP port 25 for incoming requests. The second service is usually either the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP) which is used by email client applications on users' personal computers to fetch email messages from

1728-517: Is usually associated either with malicious cracking attempts or with network administrators looking for possible vulnerabilities to help prevent such attacks. Port connection attempts are frequently monitored and logged by hosts. The technique of port knocking uses a series of port connections (knocks) from a client computer to enable a server connection. An example of the use of ports is the delivery of email . A server used for sending and receiving email generally needs two services. The first service

1792-541: The IETF , partly in response to formal IETF standardization of version 4 of the Network File System in December 2000 as IETF RFC 3010; however, those SMB-related Internet-Drafts expired without achieving any IETF standards-track approval or any other IETF endorsement. (See http://ubiqx.org/cifs/Intro.html for historical detail.) SMB2 is also a relatively clean break with the past. Microsoft's SMB1 code has to work with

1856-515: The Kerberos protocol to authenticate users against Active Directory on Windows domain networks. On simpler, peer-to-peer networks, SMB uses the NTLM protocol. Windows NT 4.0 SP3 and later can digitally sign SMB messages to prevent some man-in-the-middle attacks . SMB signing may be configured individually for incoming SMB connections (by the "LanmanServer" service) and outgoing SMB connections (by

1920-458: The TCP and IP protocols for transport. This combination allows file sharing over complex, interconnected networks , including the public Internet. The SMB server component uses TCP port 445. SMB originally operated on NetBIOS over IEEE 802.2 - NetBIOS Frames or NBF - and over IPX/SPX , and later on NetBIOS over TCP/IP (NetBT), but Microsoft has since deprecated these protocols. On NetBT,

1984-501: The cifs-utils package. The package is from the Samba maintainers. NSMB (Netsmb and SMBFS) is a family of in-kernel SMB client implementations in BSD operating systems. It was first contributed to FreeBSD 4.4 by Boris Popov, and is now found in a wide range of other BSD systems including NetBSD and macOS . The implementations have diverged significantly ever since. The macOS version of NSMB

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2048-501: The well-known ports , the registered ports , and the dynamic or private ports . The well-known ports (also known as system ports ) are those numbered from 0 through 1023. The requirements for new assignments in this range are stricter than for other registrations. The registered ports are those from 1024 through 49151. IANA maintains the official list of well-known and registered ranges. The dynamic or private ports are those from 49152 through 65535. One common use for this range

2112-516: The "LanmanWorkstation" service). The default setting for Windows domain controllers running Windows Server 2003 and later is to not allow unsigned incoming connections. As such, earlier versions of Windows that do not support SMB signing from the get-go (including Windows 9x ) cannot connect to a Windows Server 2003 domain controller. SMB supports opportunistic locking (see below) on files in order to improve performance. Opportunistic locking support has changed with each Windows Server release. In

2176-561: The CIFS moniker but continues developing SMB and publishing subsequent specifications. Samba is a free software reimplementation of the SMB protocol and the Microsoft extensions to it. Server Message Block (SMB) enables file sharing , printer sharing , network browsing, and inter-process communication (through named pipes ) over a computer network . SMB serves as the basis for Microsoft's Distributed File System implementation. SMB relies on

2240-412: The Linux kernel. Compared to user-space implementations, it provides better performance and makes it easier to implement some features such as SMB Direct. It supports SMB 3.1.1 and previous versions. Over the years, there have been many security vulnerabilities in Microsoft's implementation of the protocol or components on which it directly relies. Other vendors' security vulnerabilities lie primarily in

2304-466: The SMB 1.0 protocol, that it performs more poorly than other protocols like FTP . Monitoring reveals a high degree of "chattiness" and a disregard of network latency between hosts. For example, a VPN connection over the Internet will often introduce network latency. Microsoft has explained that performance issues come about primarily because SMB 1.0 is a block-level rather than a streaming protocol, that

2368-423: The SMB are proprietary and were initially closed, thereby forcing other vendors and projects to reverse-engineer the protocol to interoperate with it. The SMB 1.0 protocol was eventually published some time after it was reverse engineered, whereas the SMB 2.0 protocol was made available from Microsoft's Open Specifications Developer Center from the outset. In 1991, Andrew Tridgell started the development of Samba,

2432-422: The SMB protocol, opportunistic locking is a mechanism designed to improve performance by controlling caching of network files by the client. Unlike traditional locks , opportunistic lock (OpLocks) are not strictly file locking or used to provide mutual exclusion. There are four types of opportunistic locks. The use of the SMB protocol has often correlated with a significant increase in broadcast traffic on

2496-554: The aim of turning DOS INT 21h local file access into a networked file system. Microsoft made considerable modifications to the most commonly used version and included SMB support in the LAN Manager operating system it had started developing for OS/2 with 3Com around 1990. Microsoft continued to add features to the protocol in Windows for Workgroups ( c.  1992 ) and in later versions of Windows. LAN Manager authentication

2560-462: The attacker. Port (computer networking) In computer networking , a port or port number is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service. At the software level, within an operating system , a port is a logical construct that identifies a specific process or a type of network service . A port at the software level is identified for each transport protocol and address combination by

2624-448: The configurable NQ solution. MoSMB is a user space SMB implementation for Linux. It supports SMB 2.x and SMB 3.x. Key features include Cloud-scale Active-Active Scale-out Clusters, SMB Direct (RDMA), SMB Multichannel, Transparent Failover and Continuous Availability. MoSMB also supports Amazon S3 object storage as storage backend in addition to POSIX file systems such as ext4 , ZFS , Lustre , Ceph , etc. Fusion File Share by Tuxera

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2688-493: The design and maintenance of a Microsoft network. Since the release of Windows 2000, the use of WINS for name resolution has been deprecated by Microsoft, with hierarchical Dynamic DNS now configured as the default name resolution protocol for all Windows operating systems. Resolution of (short) NetBIOS names by DNS requires that a DNS client expand short names, usually by appending a connection-specific DNS suffix to its DNS lookup queries. WINS can still be configured on clients as

2752-446: The dynamic port range (see below). In some applications, the clients and the server each use specific port numbers assigned by the IANA. A good example of this is DHCP in which the client always uses UDP port 68 and the server always uses UDP port 67. Port numbers are sometimes seen in web or other uniform resource locators (URLs). By default, HTTP uses port 80 and HTTPS uses port 443, but

2816-455: The internal address of an endpoint used only within the node. On March 26, 1972, Vint Cerf and Jon Postel called for documenting the then-current usages and establishing a socket number catalog in RFC 322. Network administrators were asked to submit a note or place a phone call, "describing the function and socket numbers of network service programs at each HOST". This catalog was subsequently published as RFC 433 in December 1972 and included

2880-587: The maximum block size to 64K. SMB2 uses 32- or 64-bit wide storage fields, and 128 bits in the case of file-handles , thereby removing previous constraints on block sizes, which improves performance with large file transfers over fast networks. Windows Vista/ Server 2008 and later operating systems use SMB2 when communicating with other machines also capable of using SMB2. SMB1 continues in use for connections with older versions of Windows, as well various vendors' NAS solutions. Samba 3.5 also includes experimental support for SMB2. Samba 3.6 fully supports SMB2, except

2944-519: The modification of user quotas using the Windows quota management tools. When SMB2 was introduced it brought a number of benefits over SMB1 for third party implementers of SMB protocols. SMB1, originally designed by IBM , was reverse engineered , and later became part of a wide variety of non-Windows operating systems such as Xenix , OS/2 and VMS ( Pathworks ). X/Open standardized it partially; Microsoft had submitted Internet-Drafts describing SMB2 to

3008-405: The network. A socket number for a remote host was a 40-bit quantity. The first 32 bits were similar to today's IPv4 address, but at the time the most-significant 8 bits were the host number. The least-significant portion of the socket number (bits 33 through 40) was an entity called Another Eightbit Number , abbreviated AEN. Today, network socket refers to a related but distinct concept, namely

3072-399: The new protocol. SMB2 reduces the 'chattiness' of the SMB 1.0 protocol by reducing the number of commands and subcommands from over a hundred to just nineteen. It has mechanisms for pipelining , that is, sending additional requests before the response to a previous request arrives, thereby improving performance over high- latency links. It adds the ability to compound multiple actions into

3136-489: The operation of IP networks. Conversely, the client end of a connection typically uses a high port number allocated for short-term use, therefore called an ephemeral port . IANA is responsible for the global coordination of the DNS root, IP addressing, and other protocol resources. This includes the registration of commonly used TCP and UDP port numbers for well-known internet services. The port numbers are divided into three ranges:

3200-439: The port number assigned to it. The most common transport protocols that use port numbers are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP); those port numbers are 16-bit unsigned numbers . A port number is always associated with a network address of a host , such as an IP address , and the type of transport protocol used for communication. It completes the destination or origination address of

3264-420: The same IP address with the same protocol. Applications implementing common services often use specifically reserved well-known port numbers for receiving service requests from clients. This process is known as listening , and involves the receipt of a request on the well-known port potentially establishing a one-to-one server-client dialog, using this listening port. Other clients may simultaneously connect to

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3328-506: The same listening port; this works because a TCP connection is identified by a tuple consisting of the local address, the local port, the remote address, and the remote port. The well-known ports are defined by convention overseen by the Internet Assigned Numbers Authority (IANA). In many operating systems special privileges are required for applications to bind to these ports because these are often deemed critical to

3392-414: The sending and receiving hosts but also by other components of the networking infrastructure. In particular, firewalls are commonly configured to differentiate between packets based on their source or destination port numbers. Port forwarding is an example application of this. The practice of attempting to connect to a range of ports in sequence on a single host is commonly known as port scanning . This

3456-456: The server component uses three TCP or UDP ports: 137 (NETBIOS Name Service), 138 (NETBIOS Datagram Service), and 139 (NETBIOS Session Service). In Microsoft Windows, two vaguely named Windows services implement SMB. The "Server" service (ID: LanmanServer ) is in charge of serving shared resources . The "Workstation" service (ID: LanmanWorkstation ) maintains the computer name and helps access shared resources on other computers. SMB uses

3520-409: The server. The POP service listens on TCP port number 110. Both services may be running on the same host computer, in which case the port number distinguishes the service that was requested by a remote computer, be it a user's computer or another mail server. While the listening port number of a server is well defined (IANA calls these the well-known ports), the client's port number is often chosen from

3584-431: The source port is optional and a value of zero means no port . A process associates its input or output channels via an internet socket , which is a type of file descriptor , associated with a transport protocol , a network address such as an IP address , and a port number. This is known as binding . A socket is used by a process to send and receive data via the network. The operating system's networking software has

3648-417: The task of transmitting outgoing data from all application ports onto the network, and forwarding arriving network packets to processes by matching the packet's IP address and port number to a socket. For TCP, only one process may bind to a specific IP address and port combination. Common application failures, sometimes called port conflicts , occur when multiple programs attempt to use the same port number on

3712-612: The time) was introduced with Windows 8.1 and Windows Server 2012 R2; in those and later releases, the earlier SMB version 1 can be optionally disabled to increase security. SMB 3.1.1 was introduced with Windows 10 and Windows Server 2016 . This version supports AES-128 GCM encryption in addition to AES-128 CCM encryption added in SMB3, and implements pre-authentication integrity check using SHA-512 hash. SMB 3.1.1 also makes secure negotiation mandatory when connecting to clients using SMB versions that support it. The specifications for

3776-452: Was fraught with compatibility problems though. Non-default support for SMB2 appeared in fact in OS X 10.7, when Apple abandoned Samba in favor of its own SMB implementation called SMBX after Samba adopted GPLv3 . The Linux kernel 's CIFS client file system has SMB2 support since version 3.7. SMB 2.1, introduced with Windows 7 and Server 2008 R2, introduced minor performance enhancements with

3840-578: Was implemented based on the original legacy SMB specification's requirement to use IBM "LAN Manager" passwords, but implemented DES in a flawed manner that allowed passwords to be cracked. Later, Kerberos authentication was also added. The Windows domain logon protocols initially used 40-bit encryption outside of the United States , because of export restrictions on stronger 128-bit encryption (subsequently lifted in 1996 when President Bill Clinton signed Executive Order 13026 ). SMB 1.0 (or SMB1)

3904-599: Was introduced in Windows Server 2022 . In 1996, Microsoft published a version of SMB 1.0 with minor modifications under the Common Internet File System ( CIFS / s ɪ f s / ) moniker. CIFS was compatible with even the earliest incarnation of SMB, including LAN Manager 's. It supports symbolic links, hard links, and larger file size, but none of the features of SMB 2.0 and later. Microsoft's proposal, however, remained an Internet Draft and never achieved standard status. Microsoft has since discontinued

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3968-464: Was originally designed for small LANs ; it has a block size that is limited to 64K, SMB signing creates an additional overhead and the TCP window size is not optimized for WAN links. Solutions to this problem include the updated SMB 2.0 protocol, Offline Files , TCP window scaling and WAN optimization devices from various network vendors that cache and optimize SMB 1.0 and 2.0. Barry Feigenbaum originally designed SMB at IBM in early 1983 with

4032-531: Was originally designed to run on NetBIOS Frames (NetBIOS over IEEE 802.2 ). Since then, it has been adapted to NetBIOS over IPX/SPX (NBX), and NetBIOS over TCP/IP (NetBT). Also, since Windows 2000 , SMB runs on TCP using TCP port 445, a feature known as "direct host SMB". There is still a thin layer (similar to the Session Message packet of NetBT's Session Service) between SMB and TCP. Windows Server 2003, and legacy NAS devices use SMB1 natively. SMB1

4096-638: Was originally developed in 1983 by Barry A. Feigenbaum at IBM to share access to files and printers across a network of systems running IBM's IBM PC DOS . In 1987, Microsoft and 3Com implemented SMB in LAN Manager for OS/2 , at which time SMB used the NetBIOS service atop the NetBIOS Frames protocol as its underlying transport. Later, Microsoft implemented SMB in Windows NT 3.1 and has been updating it ever since, adapting it to work with newer underlying transports: TCP/IP and NetBT . SMB over QUIC

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