The NFS versions used by Oracle Linux 10 rely on Remote Procedure Calls (RPC) between clients and servers. To share or mount NFS file systems, the following required services work together, depending on which version of NFS is implemented. Note that all these services are started automatically:

nfsd

Server kernel module that services requests for shared NFS file systems.

rpcbind

Acts as a central "directory" service for NFS (and other RPC) services. Because some NFS services use dynamic ports, clients contact rpcbind on the server to find out which ports to use.

rpc.mountd

Process that's used by an NFS server to process mount requests from NFSv3 clients. The service checks that the requested NFS share is exported by the NFS server.

rpc.nfsd

Process that lets explicit NFS versions and protocols the server advertises to be defined.

lockd

Kernel thread that runs on both clients and servers. The lockd process implements the Network Lock Manager (NLM) protocol, which lets NFSv3 clients lock files on the server. The daemon is started automatically whenever the NFS server is run and whenever an NFS file system is mounted.

rpc-statd

Process that implements the Network Status Monitor (NSM) RPC protocol, which notifies NFS clients when an NFS server is restarted without first being brought down. The rpc-statd service is automatically started by the nfs-server service. This service doesn't require configuration by the user and isn't used with NFSv4.

rpc-idmapd

Process that provides NFSv4 client and server upcalls, which map between on-the-wire NFSv4 names (strings in the form of user@domain) and local UIDs and GIDs. The ID mapping service isn't enabled by default and must be explicitly started when using NFSv4. For the idmapd process to operate correctly, you must configure the /etc/idmapd.conf file with the appropriate domain and settings for the network. Note that only NFSv4 uses the rpc-idmapd service, earlier NFS versions don't require it, because they use numeric IDs directly.