ORA-12641: Authentication service failed to initialize

Issue:
[oracle@linux01 ~]$ sqlplus system@orcldb

SQL*Plus: Release 11.2.0.3.0 Production on Fri Nov 15 06:44:44 2013

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

Enter password:
ERROR:
ORA-12641: Authentication service failed to initialize

Solution:
Step 1: Open the sqlnet.ora file present at $ORACLE_HOME/network/admin location 
Step 2: Check the value for parameter SQLNET.AUTHENTICATION_SERVICES
Step 3: If the value for SQLNET.AUTHENTICATION_SERVICES is ALL 

The contents of sqlnet.ora are as mentioned below
[oracle@linux01 admin]$ cat sqlnet.ora
# sqlnet.ora Network Configuration File: /u01/app/oracle/product/112030/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.

# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.

SQLNET.AUTHENTICATION_SERVICES= (ALL)

Step 4: Change the value for SQLNET.AUTHENTICATION_SERVICES to NONE

SQLNET.AUTHENTICATION_SERVICES= (NONE)