openSolaris 2008 - Ensuring Compatibility With +/- Syntax - System Administration Guide: Naming and Directory Services (DNS, NIS, and LDAP)

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

NIS+. To provide +/- semantics with NIS+, change the passwd and groups sources to compat. Then, add a passwd_compat: nisplus entry to the nsswitch.conf file after the passwd or group entry as shown below.
```
passwd: compat
passwd_compat: nisplus
group: compat
group_compat: nisplus
```
The above specifies that client routines obtain their network information from /etc files and NIS+ tables as indicated by the +/- entries in the files.
NIS. To provide the same syntax as in the Solaris 4.x release, change the passwd and groups sources to compat.
```
passwd: compat
group: compat
```
Specifies the /etc files and NIS maps as indicated by the +/- entries in the files.

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 gives you results as if the table were empty even if the table has entries.