Connecting with sys user with Or without pwd

As we know "SYS" & "SYSDBA" is superuser privilege in oracle database.

There is two method to connect SYSDBA user.

1. WITH PASSWORD

2. WITHOUT PASSWORD

For example:

SQL> CONN / AS SYSDBA ---without password



For without password need follow thing to be done.

1. Oracle Database User must have SYSDBA privileges.

2. Operating System User must add in DBA group.

On windows: ORA_DBA group

On linux: DBA group

3. In sqlnet.ora file must content "NTS" in below line

SQLNET.AUTHENTICATION_SERVICES=(NTS)

For example:
SQL> CONN SYS/PWD AS SYSDBA --- with password or prevent to connect without password.

1. Remove OS user from DBA group

2. Edit sqlnet.ora file and change "NONE" to "NTS" in below line

SQLNET.AUTHENTICATION_SERVICES=(NONE)

Default Value is NTS when sqlnet.ora file created.