An existing connection was forcibly closed by the remote host

Question

I have a fat VB.NET Winform client that is using the an old asmx style web service. Very often, when I perform query that takes a while or pass a large amt of data to a web service in a dataset, I get the subject error.

The error seems to occur in < 1 min, which is far less than the web service timeout value that I have set or the timeout value on the ADO Command object that is performing the query within the web server.

It seems to occur whenever I am performing a large query that expects to return a lot of rows or when I am sending up a large amount of data to the web service. For example, it just occurred when I was passing a large dataset to the web server:

System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
   at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
   at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   --- End of inner exception stack trace ---
   at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.Connection.SyncRead(HttpWebRequest request, Boolean userRetrievedStream, Boolean probeRead)
   --- End of inner exception stack trace ---
   at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request)
   at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
   at Smit.Pipeline.Bo.localhost.WsSR.SaveOptions(String emailId, DataSet dsNeighborhood, DataSet dsOption, DataSet dsTaskApplications, DataSet dsCcUsers, DataSet dsDistinctUsers, DataSet dsReferencedApplications) in C:\My\Code\Pipeline2\Smit.Pipeline.Bo\Web References\localhost\Reference.vb:line 944
   at Smit.Pipeline.Bo.Options.Save(TaskApplications updatedTaskApplications) in 

I've been looking a tons of postings on this error and it is surprising at how varied the circumstances which cause this error are. I've tried messing with Wireshark, but I am clueless how to use it.

This application only has about 20 users at any one time and I am able to reproduce this error in the middle of the night when probably no one is using the app, so I don't think that the number of requests to the web server or to the database is high. I'm probably the only person using the app right now and I just got the error now. It seems to have to do everything with the amt of data being passed in either direction.

This error is really chronic and killing me. Please help.

Answer 1

Check your client's app.config binding setting and see if you have specified a Max message size. The default value for this is 65536

To change this, either put it in your binding configuration (maxReceivedMessageSize, maxBufferSize and maxArrayLength are key properties for this) in your app.config, or programmatically by changing the property on the binding, like so

System.ServiceModel.BasicHttpBinding binding = new System.ServiceModel.BasicHttpBinding();

// if you are getting a LOT of data back, you will need to up Message Size
binding.MaxReceivedMessageSize = int.MaxValue; 

If this doesnt solve your issue, you will have to check the server side's event log for details. The message means that the client didnt expect the connection to close, but it did, and it could mean many different things.

If possible, use WCF for web services. It solves a lot of problems that ASMX services still suffer from.

To increase the server side transmission limit and execution timeout, use this

<configuration>
  <system.web> 
    <httpRuntime maxMessageLength="409600" executionTimeoutInSeconds="300"/> 
  </system.web>
</configuration>