System Administration Guide: Naming and Directory Services (NIS+)

Ensuring NIS-NIS+ Compatibility With +/- Syntax

If +/- is used in /etc/passwd, /etc/shadow, and /etc/group files, you will need to modify the nsswitch.conffile to insure compatibility.

Note –

Users working on a client machine being served by an NIS+ server running in NIS compatibility mode cannot run ypcat on the netgroup table. Doing so will give you results as if the table were empty even if it has entries.