The Network File System (NFS) version 4 protocol is a distributed file system protocol that owes its heritage to NFS protocol version 2 (RFC 1094) and version 3 (RFC 1813). Unlike earlier versions@ the NFS version 4 protocol supports traditional file access while integrating support for file locking and the MOUNT protocol. In addition@ support for strong security (and its negotiation)@ COMPOUND operations@ client caching@ and internationalization has been added. Of course@ attention has been applied to making NFS version 4 operate well in an Internet environment. RFC 7530 formally obsoletes RFC 3530. This document@ together with RFC 7530@ replaces RFC 3530 as the definition of the NFS version 4 protocol.