官方解释sqlplus /nolog conn /as sysdba无密码可登陆

CONN / AS SYSDBA give ORA-01031

In windows, If you have such error:

SQL> conn / as sysdba
ERROR:
ORA-01031: insufficient privileges

Check the sqlnet.ora first

SQLNET.AUTHENTICATION_SERVICES = (NTS)

This allows any privileged user defined in the NT user group (named ORA_<sid>_DBA or ORA_DBA) to login to database without providing a password.

To disable this, comment this line or change it to:

SQLNET.AUTHENTICATION_SERVICES = (NONE)

After solve this issue, open a new sqlplusw, you should able to see:

SQL> conn / as sysdba
Connected.
SQL>

Remarks: Following information can be found in the Application log with event viewer.

Event Type: Information
Event Source: Oracle.orcl
Event Category: None
Event ID: 34
Date: 8/8/2005
Time: 3:44:31 PM
User: N/A
Computer: AIX
Description:
The description for Event ID ( 34 ) in Source ( Oracle.orcl ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: ACTION : 'CONNECT' DATABASE USER: '/' PRIVILEGE : NONE CLIENT USER: donghua CLIENT TERMINAL: AIX STATUS: 1031 .