Managing NFS and NIS, 2nd Edition - Mike Eisler [189]
100005 1 tcp 32795 mountd
100005 2 tcp 32795 mountd
100005 3 tcp 32795 mountd
100003 2 udp 2049 nfs
100003 3 udp 2049 nfs
100227 2 udp 2049
100227 3 udp 2049
100003 2 tcp 2049 nfs
100003 3 tcp 2049 nfs
100227 2 tcp 2049
100227 3 tcp 2049
The output from rpcinfo shows the RPC program and version numbers, the protocols supported, the IP port used by the RPC server, and the name of the RPC service. Service names come from the rpc.bynumber NIS map; if no name is printed next to the registration information then the RPC program number does not appear in the map. This may be expected for third-party packages that run RPC server daemons, since the hardware vendor creating the /etc/rpc file doesn't necessarily list all of the software vendors' RPC numbers. However, a well-known RPC service should be listed properly. Missing RPC service names could indicate a corrupted or incomplete rpc.bynumber NIS map. One exception is the NFS ACL service, defined as RPC program 100227. Solaris does not list it in /etc/rpc, and therefore its name is not printed in the previous output. The NFS ACL service implements the protocol used between Solaris hosts to exchange ACL (Access Control List) information, though it is currently only interoperable between Solaris hosts. If the client or server do not implement the service, then traditional Unix file access control based on permission bits is used.
If the portmapper on the remote machine has died or is not accepting connections for some reason, rpcinfo times out attempting to reach it and reports the error. This is a good first step toward diagnosing any RPC-related problem: verify that the remote portmapper is alive and returning valid RPC service registrations.
rpcinfo can also be used like ping for a particular RPC server:
rpcinfo -u host program version UDP-based services
rpcinfo -t host program version TCP-based services
The -u or -t parameter specifies the transport protocol to be used — UDP or TCP, respectively. The hostname must be specified, even if the local host is being queried. Finally, the RPC program and version number are given; the program may be supplied by name (one reported by rpcinfo -p) or by explicit numerical value.
As a practical example, consider trying to mount an NFS filesystem from server mahimahi. You can mount it successfully, but attempts to operate on its files hang the client. You can use rpcinfo to check on the status of the NFS RPC daemons on mahimahi:
% rpcinfo -u mahimahi nfs 2
program 100003 version 2 ready and waiting
In this example, the NFS v2 RPC service is queried on remote host mahimahi. Since the service is specified by name, rpcinfo looks it up in the rpc NIS map. The -u flag tells rpcinfo to use the UDP protocol. If the -t option had been specified instead, rpcinfo would have reported the status of the NFS over TCP service. At the time of this writing, a handful of vendors still do not support NFS over TCP, therefore a -t query to one of their servers would report that rpcinfo could not find a registration for the service using such a protocol.
rpcinfo -u and rpcinfo -t call the null procedure (procedure 0) of the RPC server. The null procedure normally does nothing more than return a zero-length reply. If you cannot contact the null procedure of a server, then the health of the server daemon process is suspect. If the daemon never started running, rpcinfo would have reported that it couldn't find the server daemon at all. If rpcinfo finds the RPC server daemon but can't get a null procedure reply from it, then the daemon is probably hung.
Debugging RPC problems
In the previous examples, we used rpcinfo to see if a particular service was registered or not. If the RPC service is not registered, or if you can't reach the RPC server daemon, it's likely there is a low-level problem in the network. However, sometimes you reach an RPC server, but you find the wrong one or it gives you the wrong answer. If you have a heterogeneous environment and are running multiple versions of each RPC service, it's possible to get RPC version