OS Authentication on Oracle Server in 11gr2

Connect as sysdba

should be oracle user and os user same
in my case oracle is os user

SQL>
SQL>
SQL>
SQL> create user "OPS$ORACLE" identified by externally;

User created.

SQL> grant connect,resource to "OPS$ORACLE";

Grant succeeded.

SQL> show parameter auth

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
ldap_directory_sysauth               string      no
os_authent_prefix                    string      ops$
remote_os_authent                    boolean     FALSE
SQL>
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
bash-3.2$
bash-3.2$
bash-3.2$ sqlplus /

SQL*Plus: Release 11.2.0.1.0 Production on Wed Jul 22 12:06:26 2015

Copyright (c) 1982, 2009, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> show user
USER is "OPS$ORACLE"
SQL>