Network File System (NFS) is a protocol that enables system administrators to share all or a portion of a file system on a networked server to make it accessible to remote computer users. NFS is a distributed file system that allows users to access files and directories on remote systems as if they were stored locally. NFS uses Remote Procedure Calls (RPCs) to route requests between clients and servers.

NFS is an application layer protocol, meaning that it can operate over any transport or network protocol stack. However, in most cases, NFS is implemented on systems running the TCP/IP protocol suite. NFS is one of the most widely used protocols for file servers, and it is available for most modern operating systems, including Linux, Microsoft Windows, IBM AIX, Oracle Solaris, and Hewlett Packard Enterprise HP-UX.

The process of setting up NFS service includes the installation of the NFS server, which can be done using the command line. Once the NFS server is installed, it can be started using the command line as well. NFS allows a system to share directories and files with others over a network. By using NFS, users and programs can access files on remote systems almost as if they were stored locally.

In summary, NFS is a protocol that allows users on client computers to access files on a network, making it a distributed file system. NFS enables system administrators to share all or a portion of a file system on a networked server to make it accessible to remote computer users. NFS is widely used for file servers and is available for most modern operating systems.