CIFS, or Common Internet File System, is a network file sharing protocol that allows applications to read and write to files and request services from server programs. It enables users to access files over a network in a way that is similar to accessing local files on their computers. CIFS is widely used in Windows environments and supports various features like file locking, file permissions, and network browsing. Originally developed by Microsoft, CIFS is an extension of the Server Message Block (SMB) protocol. It facilitates communication between different devices on a network, making it easier for users to share files and printers. CIFS is commonly used in enterprise settings, allowing seamless collaboration and data access across multiple systems.