Installation guide

Chapter 10. Network File System (NFS)
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When exporting an NFS share as read-only, consider using the all_squash option. This option
makes every user accessing the exported file system take the user ID of the nfsnobody user.
10.8. NFS and rpcbind
Note
The following section only applies to NFSv2 or NFSv3 implementations that require the rpcbind
service for backward compatibility.
The rpcbind
1
utility maps RPC services to the ports on which they listen. RPC processes notify
rpcbind when they start, registering the ports they are listening on and the RPC program numbers
they expect to serve. The client system then contacts rpcbind on the server with a particular RPC
program number. The rpcbind service redirects the client to the proper port number so it can
communicate with the requested service.
Because RPC-based services rely on rpcbind to make all connections with incoming client requests,
rpcbind must be available before any of these services start.
The rpcbind service uses TCP wrappers for access control, and access control rules for rpcbind
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.mountd and rpc.statd contain information regarding
the precise syntax for these rules.
10.8.1. Troubleshooting NFS and rpcbind
Because rpcbind
1
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 rpcbind 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).
To make sure the proper NFS RPC-based services are enabled for rpcbind, issue the following
command as root:
rpcinfo -p
The following is sample output from this command:
program vers proto port
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