NFS Services Administrator's Guide (B.11.31.03) August 2008

The following sample entry from the /etc/passwd file indicates that users in the
netgroup animals must be looked up in the NIS passwd database:
+@animals
The animals netgroup is defined in the /etc/netgroup file, as follows:
animals (-,mickey, ) (-,daffy, ) (-,porky, ) (-,bugs, )
The /etc/passwd file is searched sequentially. As a result, user mickey, daffy,
porky, or bugs appear before the animals netgroup in the /etc/passwd file. The
NIS database is not consulted for information on that user.
Netgroups can also be used to prevent lookups of certain users in the NIS passwd
database. The following sample entries from the /etc/passwd file indicate that if the
NIS passwd database contains entries for users in the bears netgroup, these entries
cannot be used on the local system. Any other user can be looked up in the NIS database.
-@bears
For more information on NIS, see NIS Administrator’s Guide (5991-2187).
For information on the /etc/passwd file, see passwd(4).
Using Netgroups in the /etc/group File
In the /etc/group file, netgroups can be used to indicate whether group information
about certain users must be looked up in the NIS group database.
The following sample entry from the /etc/group file indicates that group information
for users in the netgroup animals can be found in the NIS group database:
+@animals
The animals netgroup is defined in the /etc/netgroup file, as follows:
animals (-,mickey, ) (-,daffy, ) (-,porky, ) (-,bugs, )
Members of the animals netgroup can belong to groups listed in the local /etc/group
file as well as in the NIS group database. The following entries in the /etc/group
file give users bugs and daffy membership in the group wiseguys and in any group
in the NIS database that includes them as members:
wiseguys::22:bugs,daffy
+@animals
Netgroups can also be used in the /etc/group file to prevent lookups for certain
users. The bears netgroup is defined in the /etc/netgroup file, as follows:
bears (-,yogi, ) (-,smokey, ) (-,pooh, )
The following entries in the /etc/group file allow user pooh membership in the
group teddybears, but not in any other group listed in the NIS database or after the
-@bears entry in the /etc/group file:
teddybears::23:pooh,paddington
-@bears
For more information on NIS, see NIS Administrator’s Guide (5991-2187).
Configuring and Using NFS Netgroups 63