Steps to define external authentication method

1. Set the configuration parameter os_authent_prefix in the init.ora file as follows (the default value for the os_authent_prefix parameter is OPS$):
   
   os_authent_prefix = OPS$
   
   
   
   
2. Create a user in the following format . For example:
   
   
   

   SQL> create user ops$oracle identified externally; User created. SQL> grant connect, resource, dba to ops$oracle; Grant succeeded.

   
   
   
   Note that the new user isn’t given a password?the user doesn’t need one. As long as the user can log into the operating system, all he or she will have to do is type the following command to log in:
   
   $ sqlplus /
   
   
   
3. In order to make connection over Oracle Net set configuration parameterremote_os_authent to true:
   
   remote_os_authent=true
   
   Example of connection:
   
   $ sqlplus /@guru