SMB protocol

Kila is studying to become a Network Engineer. She is currently an intern at Google. She wants to master the SMB protocol. Please answer the following questions to improve her SMB level-of-knowledge. Kila prefers the term "Free Software" to "open-source".

  1. What is SMB and what does the SMB acronym stand for?
  2. What is the history of SMB?
  3. What are the strengths and weaknesses of SMB?
  4. What are the best use cases for SMB?
  5. What are the most used Free Software implementations of SMB?
  6. What is the likely future of SMB?

What is SMB and what does the SMB acronym stand for?

SMB stands for Server Message Block. It is a network communication protocol used for providing shared access to files, printers, and serial ports among nodes on a network. It also allows applications to read, create, and update files on the remote server. SMB operates as an application-layer network protocol mainly used for providing shared access to files, directories, and devices.

What is the history of SMB?

SMB was originally designed by IBM, with the first version appearing in the 1980s. Microsoft has since made significant modifications to the original SMB protocol, resulting in its own variants, commonly referred to as Microsoft SMB Protocol. The protocol has evolved over time through SMB1 (or SMB 1.0), SMB2, SMB2.1, SMB3, and SMB3.1.1. Each version has brought improvements in performance, security, and additional features.

What are the strengths and weaknesses of SMB?


  • Interoperability: SMB is widely supported on a variety of operating systems, including Windows, macOS, and Linux.
  • Ease of use: Users can easily access shared resources, like files and printers, with minimal configuration.
  • Integrated authentication: It supports integrated Windows authentication, which can make user management and access control easier within a Windows domain.
  • Encryption: Later versions of SMB (like SMB 3.x) provide end-to-end encryption to secure data in transit.
  • Performance: SMB2 and later versions offer significant performance improvements over the original SMB, including the ability to pipeline requests and improved error handling.


  • Complexity: SMB can be complex to configure and manage, especially in environments with different operating systems and SMB protocol versions.
  • Security: Early versions of SMB (SMB1) have known security vulnerabilities (like those exploited by the WannaCry ransomware attack). As a result, SMB1 is generally considered insecure and is being deprecated.
  • Performance over WAN: SMB performance can degrade over wide area networks (WAN) due to its chattiness and the way it handles latency.
  • Firewall Issues: SMB requires multiple ports to be open on the firewall, which can pose a security risk if not managed correctly.

What are the best use cases for SMB?

SMB is best used in:

  • Local Area Networks (LAN) for file sharing between clients and servers.
  • Enterprise environments where Windows-based systems are predominant.
  • Print services where clients need to access shared printers over a network.
  • Home or small office networks for simple and accessible file sharing and printer access.

What are the most used Free Software implementations of SMB?

The most commonly used Free Software implementation of SMB is Samba. Samba is a free software re-implementation of the SMB networking protocol, and was originally developed for UNIX systems. It provides file and print services for various Windows clients and can integrate with a Windows Server domain, either as a Domain Controller (DC) or as a domain member.

What is the likely future of SMB?

The future of SMB likely includes:

  • Continued Evolution: SMB will continue to evolve, with a focus on security and performance improvements.
  • Increased Security: In response to past vulnerabilities, future versions of SMB are likely to emphasize stronger encryption and authentication methods.
  • Cloud Integration: As cloud services become more prevalent, SMB may adapt to better support cloud storage and hybrid cloud scenarios.
  • Deprecation of SMB1: Given its security issues, SMB1 will continue to be phased out in favor of more secure versions of the protocol.
  • SMB Over QUIC: Microsoft introduced SMB over QUIC in Windows Server 2022, which operates over the QUIC transport protocol. This is designed to improve secure access to files over the internet, particularly for mobile and remote scenarios.

As a Network Engineer intern at Google, Kila would be well served to focus on understanding the latest versions of SMB, its security implications, integration with various operating systems, and the configuration of Free Software implementations such as Samba in different environments. She should also stay informed about the ongoing developments and best practices related to SMB protocol usage and management.