NFS Services Administrator's Guide

Configuring and Administering NFS Services
Configuring and Using NFS Netgroups
Chapter 290
argument in the /etc/dfs/dfstab file, any host can access the shared
directory. If a netgroup is used strictly as a list of users, it is better to put
a dash in the host field, as follows:
administrators (-,jane, ) (-,art, ) (-,mel, )
The dash indicates that no hosts are included in the netgroup.
The trusted_hosts and administrators netgroups can be used
together in the /etc/hosts.equiv file, as follows:
+@trusted_hosts +@administrators
The first netgroup is read for host names, and the second is read for user
names. Users in the administrators netgroup can log in to the local
host from any host in the trusted_hosts netgroup without supplying a
password.
The two netgroups can be combined into one, as follows:
goodguys (sage,jane, ) (basil,art, ) (thyme,mel, )
If the two netgroups are combined this way, the same netgroup can be
used as both the host name and the user name in the /etc/hosts.equiv
file, as follows:
+@goodguys +@goodguys
The first occurrence of it is read for the host name, and the second
occurrence is read for the user name. No relationship exists between the
host and user in any of the triples. For example, user jane may not even
have an account on host sage.
A netgroup can contain other netgroups, as in the following example:
root-users (dill,-, ) (sage,-, ) (thyme,- , ) (basil,-, )
mail-users (rosemary, , ) (oregano, , ) root-users
The root-users netgroup is a group of four systems. The mail-users
netgroup uses the root-users netgroup as part of a larger group of
systems. The blank space in the third field of each triple indicates that
the netgroup is valid in any NIS domain.
Using Netgroups in Configuration Files
Netgroups may be used in the following files:
• /etc/dfs/dfstab, in the [access_list], -rw, -ro, and root list