Common Internet File System (CIFS)

The Common Internet File System (CIFS) is a network file-sharing protocol that allows applications to read and write to files and request services from file servers over a network. CIFS is also known as Server Message Block (SMB), which is the name of the protocol’s predecessor. CIFS/SMB is commonly used in Windows-based environments for sharing files, printers, and other resources over a network. It’s also widely supported on other operating systems, making it a cross-platform protocol.


Common Internet File System (CIFS) features typically:

  • File Sharing: CIFS allows multiple users and applications to access files and directories on a remote server as if they were on a local file system. This enables efficient file sharing and collaboration within a network.
  • Authentication and Authorization: CIFS provides authentication mechanisms to ensure that only authorized users can access shared resources. It supports user-level permissions and access control lists (ACLs) to define who can read, write, or modify files and directories.
  • Naming and Path Resolution: CIFS uses a hierarchical naming system for files and directories, similar to the file systems on local devices. It supports both absolute and relative paths to locate and access resources on the network.
  • Session Management: CIFS establishes and manages sessions between client and server for resource access. Sessions help maintain the connection state and security context during file operations.
  • Transaction Support: CIFS allows clients to perform multiple file operations as part of a single transaction, ensuring consistency and data integrity.
  • Printing: CIFS supports print services, allowing users to send print jobs to remote printers connected to CIFS-enabled servers.
  • Browser and Discovery Services: The protocol includes a mechanism for network clients to discover available resources and servers on the network, making it easier to locate shared resources.
  • Transport Layer: CIFS can run over various transport protocols, including TCP/IP, NetBEUI, and NetBIOS over TCP/IP. TCP/IP is the most common transport used for CIFS over modern networks.
  • Versions: Over the years, CIFS has seen several versions and enhancements. SMB1, SMB2, SMB3, and SMB3.1 are the major versions, each introducing improvements in performance, security, and features.
  • Cross-Platform Compatibility: While originally developed for Windows, CIFS/SMB is supported on various operating systems, including Linux, macOS, and even some network-attached storage (NAS) devices. This cross-platform support makes it a popular choice for heterogeneous network environments.

CIFS / SMB has become the de facto standard for file sharing in Windows-based networks and is widely used in corporate environments, home networks, and cloud-based storage services. It allows users to access and share files and resources seamlessly, making it a foundational technology for networked file systems and collaborative computing.

Naming: CIFS or SMB?

The terms “Common Internet File System” (CIFS) and “SMB” (Server Message Block) are often used interchangeably because they refer to essentially the same network file-sharing protocol. However, there is some historical context and nuance to these terms:

SMB (Server Message Block)

  • Origin: SMB was originally developed by IBM in the early 1980s as a network protocol for file and printer sharing in local area networks (LANs). Microsoft later adopted and extended the SMB protocol for use in its Windows operating systems.
  • Versions: Over the years, SMB has seen several versions, including SMB1, SMB2, SMB3, and SMB3.1. Each version introduced enhancements in terms of performance, security, and features.
  • Naming: The term “SMB” is often used to refer to the protocol in general, regardless of the specific version.

CIFS (Common Internet File System)

  • Origin: CIFS is essentially an extension or enhancement of SMB. It emerged in the late 1990s as a set of improvements and additions to SMB to make it more suitable for internet-based file sharing. CIFS was intended to provide better support for wide-area networks (WANs) and the internet.
  • Enhancements: CIFS includes additional features like support for long file names, better security mechanisms, and improved performance over WAN connections.
  • Naming: “CIFS” is often used to refer to a specific version or dialect of the SMB protocol that includes these enhancements.

While SMB and CIFS are often used interchangeably, SMB typically refers to the family of protocols, including various versions like SMB1, SMB2, SMB3, etc. CIFS, on the other hand, can be thought of as a specific version or dialect of SMB with additional features and improvements aimed at better internet-based file sharing. However, in practice, the term “SMB” is commonly used to encompass both the earlier SMB versions and the later enhancements found in CIFS.

It’s worth noting that in recent years, there has been a shift away from using older SMB1 due to security vulnerabilities, and organizations and systems have been encouraged to upgrade to more secure and feature-rich versions like SMB2 or SMB3.

How to detect, enable and disable SMBv1, SMBv2, and SMBv3 in Windows

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