The Server Message Block (SMB) protocol is a communication protocol that enables applications and their users to access files on remote servers and connect to other resources, including printers, mailslots, and named pipes. It was originally developed in 1983 by IBM to provide shared access to files and printers across nodes on a network of systems running IBMs OS/2. SMB relies on the TCP and IP protocols for transport, which allows file sharing over complex, interconnected networks, including the public Internet. The SMB server component uses TCP port 445. The protocol has since spawned multiple variants, also known as dialects, to meet evolving network requirements over the years. Throughout that time, SMB has been widely implemented and continues to be one of the most popular solutions for file sharing in the workplace.
The SMB protocol works as a response-request protocol, where the client sends an SMB request to the server to initiate the connection. When the server receives the request, it sends a response back to the client. The SMB protocol enables client applications to access files on remote servers securely and control the method for opening, reading, moving, creating, and updating files on remote servers. The protocol can also communicate with server programs configured to receive SMB client requests. The SMB protocol is used by Software-defined Data Center (SDDC) computing technologies, such as Storage Spaces Direct, Storage Replica.
