I understand that rpcbind runs on NFS servers to respond to port-mapping requests from clients.
Is the rpcbind daemon needed on an NFS client?
I'm surprised that it is so difficult to find a definitive answer to this question. That might be because there's no reason to suspect that it is required.
The reason I'm asking is because I found that rpcbind is running on a number of Debian servers that are not NFS servers. And surprisingly, the nfs-common package directly depends on rpcbind, even though:
Use this package on any machine that uses NFS, either as client or server.
Related Serverfault questions:
NFS client firewall settings and rpcbind
I don't understand why nfs-common depends on rpcbind if it works without it. Am I missing anything ? Maybe rpcbind is needed for file locking or nfs stats.
Can rpcbind packagebe removed in debian wheezy, installed by default?
Yes, you can safely remove rpcbind if you don't plan on using NFS on your server.
NFS client firewall settings and rpcbind
apt-cache depends nfs-commongivesrpcbindas a direct dependency.
The NFS client uses rpcbind service on server to discover the port number used by nfsd.
More over, for clients of nfs v2 and v3, an additional rpc-statd service is used to manage locks. As rpc-statd runs on the client, a rpcbind should run on the client to let nfs servers to discover on which port rpc-statd listens.
Thus, for client that uses nfs v4, the rpcbind, rpc-statd and rpc-statd-notify services can be disabled. This can required modifying some .service files.
IOW - The rpcbind service is needed by nfs clients that use v2 and v3, as it required for file locking, and can be disabled for nfs v4 clients, as locking is a part of the NFSv4.0 protocol.