The following section only applies to NFSv2 or NFSv3 implementations that require the
portmap service for backward compatibility.
portmapper maps RPC services to the ports they are listening on. RPC processes notify
portmap when they start, registering the ports they are listening on and the RPC program numbers they expect to serve. The client system then contacts
portmap on the server with a particular RPC program number. The
portmap service redirects the client to the proper port number so it can communicate with the requested service.
Because RPC-based services rely on
portmap to make all connections with incoming client requests,
portmap must be available before any of these services start.
The Because To make sure the proper NFS RPC-based services are enabled for The following is sample output from this command:
If one of the NFS services does not start up correctly, Other useful options are available for the
portmap service uses TCP wrappers for access control, and access control rules for
portmap affect all RPC-based services. Alternatively, it is possible to specify access control rules for each of the NFS RPC daemons. The man pages for
rpc.statd contain information regarding the precise syntax for these rules.
Troubleshooting NFS and
portmap provides coordination between RPC services and the port numbers used to communicate with them, it is useful to view the status of current RPC services using
portmap when troubleshooting. The
rpcinfo command shows each RPC-based service with port numbers, an RPC program number, a version number, and an IP protocol type (TCP or UDP).
portmap, issue the following command as root:
program vers proto port
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
100021 1 udp 32774 nlockmgr
100021 3 udp 32774 nlockmgr
100021 4 udp 32774 nlockmgr
100021 1 tcp 34437 nlockmgr
100021 3 tcp 34437 nlockmgr
100021 4 tcp 34437 nlockmgr
100011 1 udp 819 rquotad
100011 2 udp 819 rquotad
100011 1 tcp 822 rquotad
100011 2 tcp 822 rquotad
100003 2 udp 2049 nfs
100003 3 udp 2049 nfs
100003 2 tcp 2049 nfs
100003 3 tcp 2049 nfs
100005 1 udp 836 mountd
100005 1 tcp 839 mountd
100005 2 udp 836 mountd
100005 2 tcp 839 mountd
100005 3 udp 836 mountd
100005 3 tcp 839 mountd
portmap is unable to map RPC requests from clients for that service to the correct port. In many cases, if NFS is not present in
rpcinfo output, restarting NFS causes the service to correctly register with
portmap and begin working. For instructions on starting NFS, refer to "Starting and Stopping NFS".
rpcinfo command. Refer to the
rpcinfo man page for more information.
To make sure the proper NFS RPC-based services are enabled for
The following is sample output from this command:
If one of the NFS services does not start up correctly,
Other useful options are available for the