NFS Services Administrator's Guide (762805-001, March 2014)

and a host in the NIS domain bldg1 shares a directory to the netgroup mydomain, any host in
the bldg1 domain may mount the directory, because the host field is blank.
If an HP-UX host not running NIS shares a directory to the netgroup mydomain, in this case, the
NIS_domain field is ignored but the host field is used. As a result, any host in any domain can
mount the directory.
If a host in the NIS domain bldg2 shares a directory to the netgroup mydomain, no host in any
domain can mount the directory, because the triple is not valid in the bldg2 domain. As a result,
it is ignored.
Netgroup Examples
The following netgroup specifies a group of hosts:
trusted_hosts (sage, , ) (basil, , ) (thyme, , )
The trusted_hosts netgroup can be used in the access_list argument of an entry in the
/etc/dfs/dfstab file, as follows:
/usr [access_list]=trusted_hosts
The following netgroup specifies a group of users:
administrators ( ,jane, ) ( ,art, ) ( ,mel, )
If this netgroup is accidentally included in a list of hosts rather than users, the blank space is
interpreted as a wildcard, meaning any host. For example, if someone used this netgroup in an
[access_list] 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.
44 Configuring and administering NFS services