1.使用操作系统验证
D:\oracle\ora92\network\admin
SQLNET.AUTHENTICATION_SERVICES = (NTS)  --启用
C:\Documents and Settings\Paul Yi>sqlplus "/as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Tue Dec 18 12:10:18 2007

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

Connected to an idle instance.

SQL> startup;
ORACLE instance started.

Total System Global Area  101785252 bytes
Fixed Size                   454308 bytes
Variable Size              75497472 bytes
Database Buffers           25165824 bytes
Redo Buffers                 667648 bytes
Database mounted.
Database opened.

2.使用密码验证
D:\oracle\ora92\network\admin
# SQLNET.AUTHENTICATION_SERVICES = (NTS)  --注释掉
使用操作系统登录方法时就报以下错误
C:\Documents and Settings\Paul Yi>sqlplus "/as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Tue Dec 18 12:04:05 2007

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

ERROR:
ORA-01031: insufficient privileges

Enter user-name:
ERROR:

C:\Documents and Settings\Paul Yi>sqlplus /nolog

SQL*Plus: Release 9.2.0.4.0 - Production on Tue Dec 18 12:04:50 2007

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

SQL> conn sys/abcdefg as sysdba
Connected.
--看到密码输错，就登录不成功，所以密码验证生效
SQL> conn sys/abcde as sysdba
ERROR:
ORA-01017: invalid username/password; logon denied

Warning: You are no longer connected to ORACLE.
SQL> startup;
ORACLE instance started.

Total System Global Area  101785252 bytes
Fixed Size                   454308 bytes
Variable Size              75497472 bytes
Database Buffers           25165824 bytes
Redo Buffers                 667648 bytes
Database mounted.
Database opened.