The NIS+ security system is complex. If you are not familiar with NIS+ security, you might want to review Chapter 11, NIS+ Security Overview before starting to configure your NIS+ environment.
The security level at which you start the server determines the credentials that its clients must have. For instance, if the server is configured with security level 2 (the default), the clients in the domain it supports must have DES credentials. If you have configured the client according to the instructions in this book, the client has DES credentials in the proper domain, and you can start the server with security level 2.
Security level 0 is for administrator configuration and testing purposes only. Security level 1 is not supported. Do not use level 0 or 1 in any environment where ordinary users are doing their normal work. Operating networks should always be run at security level 2.