You receive one or more error messages when you try to make an HTTP request in an application that is built on the .NET Framework 1.1 Service Pack 1

When you try to make an HTTP request in an application that is built on the .NET Framework, you may receive one or more of the following error messages:

Error message 1

This problem occurs when the .NET Framework cannot establish a connection to the remote server. This problem may occur when one or more of the following conditions are true:

• A network outage occurs.
• A proxy server blocks the HTTP request.
• A Domain Name System (DNS) problem occurs.
• A network authentication problem occurs.

To resolve this problem, see resolutions A, B, and C.

Error message 2

This problem occurs when the client computer cannot send an HTTP request. The client computer cannot send the HTTP request because the connection has been closed or is unavailable. This problem may occur when the client computer is sending lots of data. To resolve this problem, see resolutions A, D, E, F, and O.

Error message 3

This problem occurs when the server or another network device unexpectedly closes an existing Transmission Control Protocol (TCP) connection. This problem may occur when a time-out value on the server or on the network device is set too low. To resolve this problem, see resolutions A, D, E, F, and O. The problem can also occur if the server resets the connection unexpectedly, such as if an unhandled exception crashes the server process. Analyze the server logs to see if this may be the issue.

Error message 4

This problem occurs when the .NET Framework detects that the server response does not comply with HTTP 1.1 RFC. This problem may occur when the response contains incorrect headers or incorrect header delimiters. To resolve this problem, see resolutions A and G.

For more information about HTTP headers, visit the following World Wide Web Consortium Web site: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

Error message 5

This problem may occur when one or more of the following conditions are true:

• You are using an invalid client certificate or an invalid server certificate.
• You are experiencing a TCP connection problem.
• The client computer is sending lots of data.
• A time-out setting on the server or on another network device is set too low.
• You are experiencing an HTTPS protocol compatibility problem.

For TCP connection problems, see resolutions A, D, E, F, and O. For client certificate problems and server certificate problems, see resolutions H and I. For HTTPS protocol compatibility problems, see resolution J.

Error message 6

This problem occurs when the client time-out value is reached before one of the following conditions occurs:

• An HTTP connection is established.
• An HTTP response is received from the server.
• The data stream is completely written to or read.

To resolve this problem, see resolutions A, E, K, L, M, and N.

Note The following list contains possible resolutions that may apply when one of these problems occurs. Not all these resolutions apply to all these problems. See the problem descriptions in the "Cause" section to determine which resolution applies.

Resolution A

To resolve this problem, make sure that you are using the most recent version of the .NET Framework. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Resolution B

To resolve this problem, make sure that the proxy settings are correct. To do this, use the following techniques:

• Use the static WebProxy.GetDefaultProxy method. For more information, visit the following Microsoft Web site:
  http://msdn2.microsoft.com/en-us/library/system.net.webproxy.getdefaultproxy(vs.71).aspx

  (http://msdn2.microsoft.com/en-us/library/system.net.webproxy.getdefaultproxy(vs.71).aspx)
• Define a <proxy> element in the application configuration files. For more information, visit the following Microsoft Web site:
  http://msdn2.microsoft.com/en-us/library/aa903369(VS.71).aspx

  (http://msdn2.microsoft.com/en-us/library/aa903369(VS.71).aspx)
• Configure the .NET client to use HTTP 1.0 by changing the HttpWebRequest.ProtocolVersion property. For more information, visit the following Microsoft Web site:
  http://msdn2.microsoft.com/en-us/library/system.net.httpwebrequest.protocolversion(vs.71).aspx

  (http://msdn2.microsoft.com/en-us/library/system.net.httpwebrequest.protocolversion(vs.71).aspx)
  Note By default, the .NET Framework uses HTTP 1.1.
• If you are using Secure Sockets Layer (SSL), make sure that the proxy is not configured to use any rules that are blocking HTTPS.
• If you are using autoproxy, click the following article number to view the article in the Microsoft Knowledge Base:
  873199

  (http://support.microsoft.com/kb/873199/ )

  How to use autoproxy in managed code

Resolution C

To resolve this problem, make sure that the application has permissions to make network calls and to make socket calls. This resolution applies when the application that makes the HttpWebRequest call runs inside a Web application. You may have to grant Read permissions to the ASPNET account so that you can access the following resources:

• The Microsoft WinSockProxy WS2.0 Provider (Wspwsp.dll) file
• The
  HKLM\System\CurrentControlSet\Services\DnsCache
  registry key
• The
  HKLM\System\CurrentControlSet\Services\WinSock2
  registry key

Note To determine whether the ASPNET worker process has the necessary permissions, use the FileMon utility and the RegMon utility. To download the FileMon utility and the RegMon utility, visit the following Sysinternals Web site: The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

Resolution D

To resolve this problem, disable the keep-alive feature. In the .NET Framework, set the HttpWebRequest.KeepAlive property to FALSE. To do this when you call a Web service, follow these steps.

Note The keep-alive feature is required for NTLM authentication.

1. Create a new class by inheriting from the generated proxy class.
2. Add a method to the class to override the GetWebRequest method. This change lets you access the HttpWebRequest object. If you are using Microsoft Visual C#, the new method must be similar to the following.

   class MyTestService:TestService.TestService
   {
       protected override WebRequest GetWebRequest(Uri uri)
       {
           HttpWebRequest webRequest = (HttpWebRequest) base.GetWebRequest(uri);
           //Setting KeepAlive to false
           webRequest.KeepAlive = false;
           return webRequest;
       }
   }

   If you are using Microsoft Visual Basic .NET, the new method must be similar to the following.

   Class MyTestService 
        Inherits TestService.TestService
           Protected Overrides Function GetWebRequest(ByVal uri As Uri) As System.Net.WebRequest
               Dim webRequest As System.Net.HttpWebRequest
               webRequest = CType(MyBase.GetWebRequest(uri), System.Net.HttpWebRequest)
              'Setting KeepAlive to false 
               webRequest.KeepAlive = False
               GetWebRequest = webRequest
           End Function
   End Class

3. Create an instance of the new class, and then use the new class to call the Web service method.

Resolution E

To resolve this problem, set the ServicePointManager.MaxServicePointIdleTime property to less than the time-out value of the server keep-alive connection.

Notes

• When a ServicePoint object has been idle for the time that is specified in the MaxIdleTime property, it is eligible for garbage collection.
• Make sure that the ServicePointManager.MaxServicePointIdleTime property is set before any HTTP requests are made. For more information about the ServicePointManager.MaxSercvePointIdleTime property, visit the following Microsoft Web site:
  http://msdn2.microsoft.com/en-us/library/system.net.servicepointmanager.maxservicepointidletime(vs.71).aspx

  (http://msdn2.microsoft.com/en-us/library/system.net.servicepointmanager.maxservicepointidletime(vs.71).aspx)

Resolution F

To resolve this problem, increase the time-out value on the server computer and on other network devices. To increase the time-out value in Microsoft Internet Information Services (IIS) 6.0, follow these steps:

1. Click Start, click Control Panel, click Administrative Tools, and then click Internet Information Services (IIS) Manager.
2. Click the name of the computer that you want to reconfigure, and then click Web Sites.
3. Right-click the Web site that you want to reconfigure, and then click Properties.
4. Type a new value in the Connection timeout box, and then click OK.
5. On the File menu, click Exit.

Resolution G

To work around this problem, set useUnsafeHeaderParsing to True. For more information about the useUnsafeHeaderParsing property, click the following article number to view the article in the Microsoft Knowledge Base:

Resolution H

To resolve this problem, supply a valid client certificate for the application. For more information about how to use client certificates, click the following article numbers to view the articles in the Microsoft Knowledge Base:

Resolution I

To resolve this problem, supply a valid security certificate for the server. Additionally, you may be able to resolve this problem by installing the root certification authority (CA) certificate or by correcting the common name of the server certificate. For more information about naming the server certificate, click the following article number to view the article in the Microsoft Knowledge Base: Warning This workaround may make your computer or your network more vulnerable to attack by malicious users or by malicious software such as viruses. We do not recommend this workaround but are providing this information so that you can implement this workaround at your own discretion. Use this workaround at your own risk.

You can also revise the application code to ignore these certificate warnings. To do this, implement your own ICertificatePolicy interface. You can then set the ServicePointManager.CertificatePolicy property to use your certificate policy instance before the Web service method call is made.

Note The ICertificatePolicy.CheckValidationResult method implements the application certificate validation policy. For more information about the ICertificatePolicy.CheckValidationResult method, visit the following Microsoft Web site: For more information and a code sample, click the following article number to view the article in the Microsoft Knowledge Base: Important We recommend that you not ignore SSL certificate warnings in code because of possible security risks.

Resolution J

To resolve this problem, change the HTTPS protocol from SSL to Transport Level Security (TLS).

Note If you already use TLS, change the HTTPS protocol to SSL. To change the HTTPS protocol on the client computer, see the "ServicePointManager.SecurityProtocol property" section on the following Microsoft Web site: Note For example, to support the SSL3 protocol and the TLS1 protocol, use code that is similar to the following. For more information about how to change the HTTPS protocol on the server computer, click the following article number to view the article in the Microsoft Knowledge Base:

Resolution K

To resolve this problem, increase the value of the maxConnection property. To do this, revise the configuration files for the application or add application code.

Note The default value of the maxConnection property is 2. For Microsoft ASP.NET-connected applications that call Web services, we recommend that you set a value of 12 times the number of processors. To set this value by using application code, use the ServicePointManager.DefaultConnectionLimit property. For more information about the ServicePointManager.DefaultConnectionLimit property, visit the following Microsoft Web site: To set this value by using the configuration files for the application, add the following code to the configuration file.For more information about how to use the <connectionManagement> element, visit the following Microsoft Web site:

Resolution L

To resolve this problem, make sure that the time-out settings on the server and on other network devices are implemented correctly. For more information about how to implement time-out settings, click the following article number to view the article in the Microsoft Knowledge Base:

Resolution M

To resolve this problem, read about ASP.NET performance tuning. For more information about ASP.NET performance tuning, click the following article number to view the article in the Microsoft Knowledge Base:

Resolution N

To resolve this problem, increase the values of the time-out properties in the client application code. To do this, use the following properties:

• HttpWebRequest.Timeout
• HttpWebRequest.ReadWriteTimeout

For more information about the HttpWebRequest.Timeout property, visit the following Microsoft Web site: For more information about the HttpWebRequest.ReadWriteTimeout property, visit the following Microsoft Web site:

Resolution O

To resolve this problem, make sure that the client computer does not send the HTTP 100-Continue header. Additionally, make sure that the client computer does not expect to receive the HTTP 100-Continue header.

Note This resolution is effective if the Web server or the proxy server does not support the HTTP 100-Continue header. For more information about how to disable the HTTP 100-Continue header for the client computer, visit the following Microsoft Web site:

For more information about performance considerations when you make Web service calls from ASP.NET-connected applications, visit the following Microsoft Web site: For more information about performance issues and deadlock issues when you make Web service requests from ASP.NET-connected applications, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to improve the performance of ASP.NET-connected applications, visit the following Microsoft Web site: For more information about how to improve the performance of Web services, visit the following Microsoft Web site: For more information about how to build secure ASP.NET-connected applications, visit the following Microsoft Web site: Note The TCP transport protocol is used for HTTP requests. TCP is a reliable, connection-oriented protocol. However, if a TCP connection closes unexpectedly, the application retries the request. For more information about the TCP protocol and about client behavior if the server closes a connection, visit the following World Wide Web Consortium Web site: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information. For more information about the FileMon utility and the RegMon utility, click the following article number to view the article in the Microsoft Knowledge Base: For more information about Network Monitor, click the following article numbers to view the articles in the Microsoft Knowledge Base: