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