Oracle不可访问问题的解决

一个asp.net程序，采用oracle数据库，在windows 2003 server下面出现oracle不可访问错误，但是使用pl/sql或者winform程序均可访问oracle，发现asp.net在运行时的权限不够，在web.config文件中进行如下设置<identity impersonate="true" userName="Administrator" password="Password"/>后大部分时间可以访问oracle，但是也访问不了。后来将%oracle_home%/ora92/network/admin/sqlnet.ora文件中的SQLNET.AUTHENTICATION_SERVICES= (NTS)改为SQLNET.AUTHENTICATION_SERVICES= (NONE)，问题解决。

这个 NTS 时常引起 连接不到数据库，
择段英文如下解释
SQLNET.AUTHENTICATION_SERVICES

Purpose

Use the parameter SQLNET.AUTHENTICATION_SERVICES to enable one or more authentication services. If authentication has been installed, it is recommended that this parameter be set to either none or to one of the authentication methods.

Default

None

Values

Authentication Methods Available with Oracle Net Services:

none for no authentication methods. A valid username and password can be used to access the database.
all for all authentication methods
nts for Windows NT native authentication
Windows NT native authentication
An authentication method that enables a client single login access to a Windows NT server and a database running on the server.

If authentication is set to NTS on a standalone Windows 2000 or Windows NT 4.0 computer, ensure that Windows Service NT LM Security Support Provider is started. If this service is not started on a standalone Windows 2000 or Windows NT 4.0 computer, then NTS authentication fails. This issue is applicable only if you are running Windows 2000 or Windows NT 4.0 in standalone mode.