[ Thanks to Chris Lowth
for this link. ]
“When setting up IPTABLES firewalling for Linux systems running
the NFS service (network file system), you hit the problem that
some of the TCP/IP and UDP ports used by components of the service
are randomly generated as part of the ‘SunRPC’ mechanism.“This HOWTO document is part of the LinWiz tool kit, and
describes how to set up NFS on your server in such a way that
meaningful IPTABLES firewall rules can be applied to the
system…”