SmB

SMB commonly stands for Server Message Block in computing, a network file sharing protocol that enables applications to read and write to files and request services on remote servers in a client-server model.

Origin and implementations: The protocol originated with IBM in the 1980s as part of LAN Manager, was extended by Microsoft, and remains a core component of Windows networking. Open-source and cross-platform implementations exist, most notably Samba, which provides SMB-compatible services on Unix-like systems and interoperability with Windows.

Protocol features and versions: SMB supports file and printer sharing, named pipes for inter-process communication, and remote administration. It uses authentication via NTLM or Kerberos, supports file locking, and in SMB3 can provide encryption and improved performance. SMB1, introduced early on, is now considered insecure and often disabled; SMB2 and SMB3 introduced substantial improvements in performance, compound operations, and security. Security considerations include exposure to worms and ransomware affecting exposed SMB ports; best practices include disabling SMB1, enforcing strong authentication, and enabling SMB signing or encryption where appropriate.

SMB also stands for Small and Medium-sized Businesses, an economic category describing firms with limited employees and revenue compared with large enterprises. Definitions vary by country or organization, but typically refer to firms below certain thresholds. SMBs face IT resource constraints and often rely on scalable, cost-effective solutions, including cloud services and managed IT.

The term SMB is thus used in both networking and business contexts, and meaning is usually clear from context.