Connect as sys - When you use just " / "

When connecting as sys, you can use just " / " when:

- Your user account in Windows  belong to ora-dba group, and
-  On your sqlnet.ora, it should be setup:

 SQLNET.AUTHENTICATION_SERVICES = (NTS)

Now you can do:

C:\ SET ORACLE_SID=<My_Instance> 
C:\ sqlplus /nolog

SQL> connect / as sysdba