The daemons that process the NFS requests on the server are not assigned standard UDP port numbers.   Instead, they are dynamically assigned port numbers by the RPC(remote procedure call) portmapper.   On some systems, the portmapper program is named rpc.portmap.   On Red Hat systems, the program is named portmap, and is started by the script /etc/rc.d/init.d/portmap.

  Listing 3.0 Displaying RPC ports

   $ rpcinfo -p

   program  vers  proto  port

   100000   2  tcp   111 (portmapper)

   100000   2  udp   111 (portmapper)

   . . . . .  . . .  . . . . . . . . .. . . .

   . . . .  . . . . . . .  . . . .

   100024   1  udp   32768 (status)

   100024   1  tcp   32768 (status)

   . . .  . . .  . . . .

   100011   2  udp  687 (rquotad)

   100011   2  tcp  687 (rquotad)

   . . . . .  . . . .   . . . .

   100005  1  tcp  690 mountd

   100005  1  udp  690 mountd

   . . . .  . . . . .. . .

   100003  3  udp  2049 nfs

   100003  3  tcp  2049 nfs

   100021  4  udp  32779 nlockmgr

   100021  4  tcp  32779 nlockmgr

   . . . . . . . .  . . . .

Port number 111(portmapper) is the portmapper's own port number, which is a well known port number assigned in the /etc/services file.   (On some systems, the name associated with this port may be rpcbind or sunrpc).   If other RPC services, such as NIS, were running on this server, portmapper would also list those services in response to the rpcinfo command.

Note:

status 

   monitor reports crashes, and reboots to the lock manager.   rpc.statd monitors both TCP and UDP traffic

rquotad 

   remote quota server, rpc.rquotad, enforces filesystem quotas for NFS mounted filesystems.   

  Filesystem quotas control the amount of disk storage an individual user can consume.

mountd 

   this daemon processes the client's filesystem mount requests.   

   rpc.mountd is the program that checks whether or not a filesystem is being exported and whether or

   not the client making the request is allowed to mount the requested filesystem

nfs 

   this program handles the user-level interface to the NFS kernel module (nfsd.o).   

   The NFS file I/O is handled in the kernel module.

nlockmgr 

   the NFS lock manager(lockd) handles file-lock requests from clients.   

   Read-Only files do not require file locking