What is the difference between CIFS and SMB?

Most people, when they use either SMB or CIFS, are talking about the same exact thing.  The two are interchangeable not only in discussion, but also in application – i.e., a client speaking CIFS can talk to a server speaking SMB and vice versa.  Why?  Because CIFS is a form of SMB

SMB stands for “Server Message Block.”  It’s a file sharing protocol that was invented by IBM and has been around since the mid-eighties.  It was designed to allow computers to read and write files to a remote host over a local area network (LAN).  The directories on the remote hosts made available via SMB are called “shares.”

CIFS stands for “Common Internet File System.” CIFS is a dialect of SMB.  That is, CIFS is a particular implementation of the Server Message Block protocol, created by Microsoft.