SQLNET.AUTHENTICATION_SERVICES参数在SQLNET.ORA（位于$ORACLE_HOME/network/admin目录中） 文件中对于不同的操作系统SQLNET.AUTHENTICATION_SERVICES的取值会有些不一样，通常我们会用到下面的一些设置值：
　　linux下： none  all nts 不设置或BEQ 四种情况
　　第一种情况：
　　参数SQLNET.AUTHENTICATION_SERVICES不设置或设置为BEQ---------口令认证和操作系统认证都启动
[oracle@tygeradmin]$ pwd
/u01/app/oracle/product/10.2.0/db_1/network/admin
[oracle@tyger admin]$ ls
listener.ora  samples  shrept.lst  sqlnet.ora  tnsnames.ora
[oracle@tyger admin]$ vim sqlnet.ora
NAME.DIRECTORY_PATH=(tnsnames，ezconnect)
SQLNET.AUTHENTICATION_SERVICES=(BEQ)
[oracle@tyger admin]$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 28-FEB-2014 09:52:19
Copyright (c) 1991， 2005， Oracle.  All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=tyger )(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date                28-FEB-2014 09:48:44
Uptime                    0 days 0 hr. 3 min. 34 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=tyger )(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC0)))
Services Summary...
Service "ORCL" has 1 instance(s).
Instance "ORCL"， status READY， has 1 handler(s) for this service...
Service "ORCLXDB" has 1 instance(s).
Instance "ORCL"， status READY， has 1 handler(s) for this service...
Service "ORCL_XPT" has 1 instance(s).
Instance "ORCL"， status READY， has 1 handler(s) for this service...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc"， status UNKNOWN， has 1 handler(s) for this service...
The command completed successfully
[oracle@whgg admin]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Fri Feb 28 09:52:50 2014
Copyright (c) 1982， 2005， Oracle.  All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning， OLAP and Data Mining options
SYS@ORCL>exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning， OLAP and Data Mining options
[oracle@tyger admin]$ cd /u01/app/oracle/product/10.2.0/db_1/dbs/
[oracle@tyger dbs]$ ls
hc_ORCL.dat  initdw.ora  init.ora  lkORCL  orapwORCL  spfileORCL.ora
[oracle@tyger dbs]$ sqlplus sys/oracle@ORCL as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Fri Feb 28 09:53:51 2014
Copyright (c) 1982， 2005， Oracle.  All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning， OLAP and Data Mining options
SYS@ORCL>
　　第二种情况：
　　参数SQLNET.AUTHENTICATION_SERVICES设置为 all  -----------------------屏蔽口令认证都启用操作系统认证
[oracle@tyger admin]$ pwd
/u01/app/oracle/product/10.2.0/db_1/network/admin
[oracle@tyger admin]$ vim sqlnet.ora
NAME.DIRECTORY_PATH=(tnsnames，ezconnect)
SQLNET.AUTHENTICATION_SERVICES=(ALL)
[oracle@tyger admin]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Fri Feb 28 09:59:20 2014
Copyright (c) 1982， 2005， Oracle.  All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning， OLAP and Data Mining options
SYS@ORCL>exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning， OLAP and Data Mining options
[oracle@tyger admin]$ sqlplus sys/oracle@ORCL as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Fri Feb 28 09:59:39 2014
Copyright (c) 1982， 2005， Oracle.  All rights reserved.
ERROR:
ORA-12641: Authentication service failed to initialize
Enter user-name: