SunOS 4 Compatibility Mode

NIS supports password configuration files in both the SunOS 4 (Solaris 1) password format and the Solaris 2 password and shadow file formats.

The mode of operation is determined by the existence of the file $PWDIR/shadow, where $PWDIR is the Makefile macro set in the /var/yp/Makefile file. If the shadow file exists, NIS operates in the Solaris 2 mode. If this file does not exist, NIS operates in the SunOS 4 mode.

In the SunOS 4 mode, all password information is kept in the passwd file. In the Solaris 2 mode, password information is kept in the shadow file and the user account information is kept in the passwd file.

If the make macro PWDIR is set to the /etc directory, NIS can operate only in the Solaris 2 mode because of the Solaris 2 passwd processing requirements. However, if PWDIR points to any directory other than /etc, the user has the option of keeping passwd configuration files in either the SunOS 4 format or in the Solaris 2 format. The rpc.yppasswdd daemon understands both password formats. The Solaris 2 format is recommended.