The Common Internet File System (CIFS) is a network protocol that is used to share files between computers on a network. CIFS is an implementation of the Microsoft version of the Server Message Block (SMB) local area network file sharing protocol. CIFS builds on and extends the original version of Microsoft’s SMB protocol. Many available network products use CIFS to transfer files. Microsoft has introduced SMB 2.0 and SMB 3.0 in later versions of their operating systems, but CIFS is still a supported protocol.