Definition of CIFS, Common Internet File System, on the Network Encyclopedia.
What is Common Internet File System?
Common Internet File System, also known as CIFS, is a public version of the Server Message Block (SMB) file-sharing protocol that has been tuned for use over the Internet. Common Internet File System (CIFS) is a remote file system access protocol that enables groups of users to collaborate and share documents over the Internet or within corporate intranets.

CIFS is an open, cross-platform technology that is based on the native file-sharing protocols of Microsoft Windows platforms. It is supported by other platforms such as UNIX. CIFS is viewed as a possible replacement for both the File Transfer Protocol (FTP) and the Network File System (NFS) file system protocols. CIFS supports encrypted passwords and Unicode filenames; it can be used to mount a remote file system as a directory or drive on the local machine. CIFS also includes features not supported by NFS, including write-ahead and native support for locks.
CIFS and the IETF
Microsoft’s Distributed file system (Dfs) is covered as part of the CIFS specification. CIFS has been submitted to the Internet Engineering Task Force (IETF) by Microsoft. CIFS client and server software is available for the Windows NT operating system platform.