If your network uses NIS to authenticate users, password information is kept in the NIS password map. NIS does not support password aging. You can use the command passwd -r nis to change a user's password that is stored in an NIS password map.
If your network uses NIS+ to authenticate users, password information is kept in the NIS+ database. Information in the NIS+ database can be protected by restricting access to authorized users only. You can use the passwd -r nisplus command to change a user's password that is stored in an NIS+ database.