The NFS Version 4 protocol represents the user ID and the group ID as strings. The nfsmapid daemon is used by the NFS Version 4 client and server for the following mappings:
Map the user ID and group ID strings to local numeric IDs
Map the local numeric IDs to user ID and group ID strings
For more information about the nfsmapid daemon, see NFS Daemons.
Note that in NFS Version 4, the nfsmapid daemon, is used to map user IDs or group IDs in Access Control List (ACL) entries on a server to user IDs or group IDs in ACL entries on a client. The reverse is also true. For more information about user ID and group ID mapping, see ACLs and nfsmapid in NFS Version 4 and NFS ACL Support.
With NFS Version 4, when you unshare a file system, all the state information for any open files or file locks in that file system is destroyed. In NFS Version 3, the server maintains any locks that the clients had obtained before the file system was unshared. For more information about unsharing a file system in NFS Version 4, see Unsharing and Resharing a File System in NFS Version 4.
NFS Version 4 servers use a pseudo file system to provide clients with access to exported objects on the server. For more information about pseudo file system, see File System Namespace in NFS Version 4. NFS Version 4 supports volatile file handles. For more information, see Volatile File Handles in NFS Version 4.
Delegation, a technique by which the server delegates the management of a file to a client, is supported on both the client and the server. For example, the server could grant either a read delegation or a write delegation to a client. For more information about delegation, see Delegation in NFS Version 4.
NFS Version 4 does not support LIPKEY/SPKM security.
Also, NFS Version 4 does not use the following daemons:
lockd
nfslogd
statd
For a complete list of the features in NFS Version 4, see Features in NFS Version 4.
For information about setting up the NFS services, see Setting Up the NFS Service.