建立与SQL Server的连接时发生与网络相关或特定于实例的错误

Question

我在somee.com上部署了我的asp.net Web应用程序，每当我登录此站点（ipc.somee.com）时，它都会给我一个网络相关的错误，如：

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace: 


[SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)]
   System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction) +5296071
   System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) +558
   System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover) +5308555
   System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover) +145
   System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout) +920
   System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance) +307
   System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions) +434
   System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +5311099
   System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +37
   System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnectionOptions userOptions) +558
   System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnectionOptions userOptions) +67
   System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +1052
   System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +78
   System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +167
   System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) +143
   System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry) +83
   System.Data.SqlClient.SqlConnection.Open() +96
   Default.log(Object sender, EventArgs e) in c:\users\sreekanth\documents\visual studio 2010\Projects\IPCWebApp\IPCWebApp\Default.aspx.cs:43
   System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +115
   System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +124
   System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +35
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1724

Answer 1

当您的应用程序没有足够的权限访问数据库时，Sql Server会触发此错误。这个错误有几个原因。要修复此错误，您应该按照以下说明操作。

1. 尝试使用management studio从服务器连接sql server。如果使用Windows身份验证连接sql server，则将应用程序池标识设置为服务器管理员。

2. 如果您使用sql server身份验证，请检查Web应用程序的web.config中的连接字符串，并设置允许您登录的SQL Server的用户ID和密码。

3. 如果您的数据库在其他服务器（访问远程数据库）然后首先从sql server管理工作室启用sql server sql server属性的远程访问并启用TCP / IP表单sql server配置管理器。

4. 完成所有这些工作后你仍然无法访问数据库然后检查服务器表单的防火墙，你试图访问数据库并在防火墙中添加一条规则来启用sql server的端口（默认为sql）服务器使用1433，检查sql server的端口需要检查sql server配置管理器网络协议的TCP / IP端口）。

5. 如果您的sql server在命名实例上运行，那么您需要使用sql serer名称编写端口号，例如117.312.21.21/nameofsqlserver,1433。

6. 如果您正在使用像amazon aws或microsoft azure这样的云托管，那么服务器或实例将在云防火墙后面运行，因此如果您有用于命名的sql server的默认实例或特定端口，则需要在云防火墙中启用1433端口实例。

7. 如果您使用的是亚马逊RDS或SQL azure，则需要从该实例的安全组启用端口。

8. 如果您通过sql server身份验证模式访问sql server，请确保启用了“SQL Server和Windows身份验证模式”sql server实例属性。

   1. 在对属性进行任何更改后重新启动sql server实例，因为某些更改将需要重新启动。

如果您再遇到任何困难，那么您需要提供有关您的网站和SQL Server的更多信息。