Manual Pages  — NETGROUP

netgroup – defines network groups

SYNOPSIS DESCRIPTION NIS/YP INTERACTION FILES COMPATIBILITY SEE ALSO BUGS

netgroup

On most other platforms, Ns are only used in conjunction with NIS and local /etc/netgroup files are ignored. With FreeBSD , Ns can be used with either NIS or local files, but there are certain caveats to consider. The existing netgroup system is extremely inefficient where innetgr(3) lookups are concerned since netgroup memberships are computed on the fly. By contrast, the NIS netgroup database consists of three separate maps (netgroup, netgroup.byuser and netgroup.byhost) that are keyed to allow innetgr(3) lookups to be done quickly. The FreeBSD netgroup system can interact with the NIS netgroup maps in the following ways:

• If the /etc/netgroup file does not exist, or it exists and is empty, or it exists and contains only a '+', and NIS is running, netgroup lookups will be done exclusively through NIS, with innetgr(3) taking advantage of the netgroup.byuser and netgroup.byhost maps to speed up searches. (This is more or less compatible with the behavior of SunOS and similar platforms.)
• If the /etc/netgroup exists and contains only local netgroup information (with no NIS '+' token), then only the local netgroup information will be processed (and NIS will be ignored).
• If /etc/netgroup exists and contains both local netgroup data and the NIS '+' token, the local data and the NIS netgroup map will be processed as a single combined netgroup database. While this configuration is the most flexible, it is also the least efficient: in particular, innetgr(3) lookups will be especially slow if the database is large.

/etc/netgroup
	the netgroup database

The file format is compatible with that of various vendors, however it appears that not all vendors use an identical format.