netgroup(5)                 Linux Reference Manual                 netgroup(5)

       netgroup - specify network groups

       The  netgroup file  defines "netgroups", which are sets of (host, user,
       domain) tuples, used for permission checking when doing remote  mounts,
       remote logins and remote shells.

       Each  line  in  the file consists of a netgroup name followed by a by a
       list of members, where a member is either another netgroup name,  or  a

              (host, user, domain)

       where  the  host, user, and domain are character strings for the corre-
       sponding components. Any of the three fields can  be  empty,  in  which
       case  it  specifies  a  "wildcard", or may consist of the string "-" to
       specify "no valid value". The domain field must  either  be  the  local
       domain name or empty for the netgroup entry to be used. This field does
       not limit the netgroup or provide security. The domain field refers  to
       the  domain in which the triple is valid, not the domain containing the
       the trusted host.

       A gateway machine should be listed  under  all  possible  hostnames  by
       which it may be recognized:

              gateway (server,,) (server-sn,,) (server-bb,,)

       The  getnetgrent  functions  should normally be used to access the net-
       group database.


       getnetgrent(3), exports(5), makedbm(8), ypserv(8)

       The triple (,,domain) allows all users and machines trusted access, and
       has the same effect as the triple (,,). Use the host and user fields of
       the triple to restrict the access correctly to a specific set  of  mem-

       The Linux libc5 does not query the /etc/netgroup file directly, it only
       querys the NIS server for the groups. So the netgroup database must  be
       stored in the form of a hashed dbm database just like the passwd(5) and
       group(5) databases.

       This manpage mentions getnetgrent(3), but it seems that manpage  hasn't
       been written yet. Since getnetgrent() is part of GNU libc it might also
       be that it is documented in info format.

       Thorsten Kukuk <>

NIS                                May 1999                        netgroup(5)