Netgroups: Network-Wide Groups of Machines and Users

The /etc/netgroup file is not a standard Transmission Control Protocol/Internet Protocol (TCP/IP) file. Rather, it is strictly an NIS file that resides on the master server. NIS uses the /etc/netgroup file to generate the netgroup.byuser and netgroup.byhost maps. NIS provides these maps for authentication purposes during login, remote login, remote mount, and remote shell processes.

Specifically, the programs that consult these maps are:

login command

Consults the maps for user classifications if it encounters netgroup names in the /etc/passwd file.

rlogin command

Consults the maps for machine classifications if it encounters netgroup names in the /etc/exports file.

rlogin command and rsh command

Consult the netgroup map for both machine and user classifications if they encounter netgroup names in the /etc/hosts.equiv or /.rhosts files.

mountd daemon

Consults the maps for machine classifications if it encounters netgroup names in the /etc/exports file.