实验：

oracle服务器位于Linux操作系统，客户端位于windows操作系统。

首先，查看remote_login_passwordfile参数值：

SYS@orcl 11-SEP-14>show parameter remote_login_passwordfileNAME                                TYPE        VALUE
------------------------------------ ----------- ------------------------------
remote_login_passwordfile            string      EXCLUSIVE

SQLNET.AUTHENTICATION_SERVICES=NONE
#Purpose: Use parameter SDP.PF_INET_SDP to specify the protocol family or
#        address family constant for the SDP protocol on your system.
#
#Supported since:  11.0
#
SQLNET.AUTHENTICATION_SERVICES=none

即使用密码文件认证方式，那么如果我们在本地使用sqlplus "/as sysdba"就会提示错误信息：

[oracle@localhost ~]$ sqlplus "/as sysdba"
SQL*Plus: Release 11.2.0.1.0 Production on Fri Sep 12 22:45:56 2014Copyright (c) 1982, 2009, Oracle.  All rights reserved.ERROR:
ORA-01031: insufficient privileges

此时我们必须使用sys用户名和密码才可以登录：

[oracle@localhost ~]$ sqlplus "sys/sys as sysdba"SQL*Plus: Release 11.2.0.1.0 Production on Fri Sep 12 22:47:08 2014Copyright (c) 1982, 2009, Oracle.  All rights reserved.Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

再次使用sqlplus "/as sysdba"登录的时候使用的就是本地认证：

[oracle@localhost ~]$ sqlplus "/as sysdba"SQL*Plus: Release 11.2.0.1.0 Production on Fri Sep 12 22:49:51 2014Copyright (c) 1982, 2009, Oracle.  All rights reserved.Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

首先看看orapwd的用法：

[oracle@localhost ~]$ orapwd
Usage: orapwd file= entries= force= ignorecase= nosysdba=wherefile - name of password file (required),password - password for SYS will be prompted if not specified at command line,entries - maximum number of distinct DBA (optional),force - whether to overwrite existing file (optional),ignorecase - passwords are case-insensitive (optional),nosysdba - whether to shut out the SYSDBA logon (optional Database Vault only).There must be no spaces around the equal-to (=) character. 

我们把位于$ORACLE_HOME/dbs目录下的原orapworcl移到其它目录。注意，remote_login_passwordfile=exclusive,且sqlnet.ora中SQLNET.AUTHENTICATION_SERVICES=none

在windows上的客户端尝试远程oracle：

SQL> conn sys/sys@win as sysdba
ERROR:
ORA-01031: insufficient privileges

现在我们使用orapwd来重建密码文件：

[oracle@localhost dbs]$ orapwd file=$ORACLE_HOME/dbs/orapworcl password=sys entries=5
[oracle@localhost dbs]$ ls
hc_DBUA0.dat  initorcl      lkORCL        peshm_DUMMY_0  spfileorcl.ora
hc_orcl.dat  initorcl.ora  orapworcl      peshm_orcl_0
init.ora      lkDUMMY      peshm_DBUA0_0  snapcf_orcl.f 

再次尝试远程连接oracle：

SQL> conn sys/sys@win as sysdba
connected.

[oracle@localhost dbs]$ strings orapworcl

ORACLE Remote Password file
INTERNAL
6A75B1BBE50E66AB
4DE42795E66117AE

在数据库中创建一个新的用户并授予sysdba的权限：

SYS@orcl 11-SEP-14>create user sunny identified by sunny;User created.
SYS@orcl 11-SEP-14>grant sysdba to sunny;Grant succeeded.

[oracle@localhost dbs]$ strings orapworclORACLE Remote Password file
INTERNAL
6A75B1BBE50E66AB
4DE42795E66117AE
SUNNY
53801465943A91BE

也可以通过动态性能视图v$pwfile_users查看有哪些用户是拥有sysdba权限的：

SYS@orcl 11-SEP-14>select * from v$pwfile_users;USERNAME                        SYSDB SYSOP SYSAS
------------------------------  ----- ----- -----
SYS                             TRUE  TRUE  FALSE
SUNNY                           TRUE  FALSE FALSE