A POST or PUT request may fail when you use the HttpWebRequest class to send lots of data on a computer that is running the .NET Framework

public void test(Uri URL)
		{
			HttpWebRequest WRequest;
			HttpWebResponse WResponse;
			//preAuth the request
			// You can add logic so that you only pre-authenticate the very first request.
			// You should not have to pre-authenticate each request.
			WRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
			// Set the username and the password.
			WRequest.Credentials = new NetworkCredential(user, password);
			WRequest.PreAuthenticate = true;
			WRequest.UserAgent = "Upload Test";
			WRequest.Method = "HEAD";
			WRequest.Timeout = 10000;
			WResponse = (HttpWebResponse)WRequest.GetResponse(); 
			WResponse.Close();
			// Make the real request.
			WRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
			// Set the username and the password.
			WRequest.Credentials = new NetworkCredential(user, password);
			WRequest.PreAuthenticate = true;
			WRequest.UserAgent = "Upload Test";
			WRequest.Method = "POST";
			WRequest.AllowWriteStreamBuffering = false;
			WRequest.Timeout = 10000;
			FileStream ReadIn = new FileStream("c:\\testuploadfile.txt", FileMode.Open, FileAccess.Read);
			ReadIn.Seek(0, SeekOrigin.Begin); // Move to the start of the file.
			WRequest.ContentLength = ReadIn.Length; // Set the content length header to the size of the file.
			Byte[] FileData = new Byte[ReadIn.Length]; // Read the file in 2 KB segments.
			int DataRead = 0;
			Stream tempStream = WRequest.GetRequestStream();
			do
			{
				DataRead = ReadIn.Read(FileData,0,2048);
				if (DataRead > 0) //we have data
				{
					tempStream.Write(FileData,0,DataRead); 
					Array.Clear(FileData,0, 2048); // Clear the array.
				}
			}while(DataRead > 0);
	
			WResponse = (HttpWebResponse)WRequest.GetResponse(); 
			// Read your response data here.
			// Close all streams.
			ReadIn.Close();
			tempStream.Close();
			WResponse.Close();
		}

public void test(Uri URL)
		{
			HttpWebRequest WRequest;
			HttpWebResponse WResponse;
			CredentialCache myCredCache = new CredentialCache();
			myCredCache.Add(URL,"Negotiate",(NetworkCredential) CredentialCache.DefaultCredentials);
			// Pre-authenticate the request.
			WRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
			// Set the username and the password.
			WRequest.Credentials = myCredCache;
			// This property must be set to true for Kerberos authentication.
			WRequest.PreAuthenticate = true;
			// Keep the connection alive.
			WRequest.UnsafeAuthenticatedConnectionSharing = true;
			WRequest.UserAgent = "Upload Test";
			WRequest.Method = "HEAD";
			WRequest.Timeout = 10000;
			WResponse = (HttpWebResponse)WRequest.GetResponse(); 
			WResponse.Close();
			// Make the real request.
			WRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
			// Set the username and the password.
			WRequest.Credentials = myCredCache;
			// This property must be set to true for Kerberos authentication.
			WRequest.PreAuthenticate = true;
			// Keep the connection alive.
			WRequest.UnsafeAuthenticatedConnectionSharing = true;
			WRequest.UserAgent = "Upload Test";
			WRequest.Method = "POST";
			WRequest.AllowWriteStreamBuffering = false;
			WRequest.Timeout = 10000;
			FileStream ReadIn = new FileStream("c:\\ testuploadfile.txt ", FileMode.Open, FileAccess.Read);
			ReadIn.Seek(0, SeekOrigin.Begin); // Move to the start of the file.
			WRequest.ContentLength = ReadIn.Length; // Set the content length header to the size of the file.
			Byte[] FileData = new Byte[ReadIn.Length]; // Read the file in 2 KB segments.
			int DataRead = 0;
			Stream tempStream = WRequest.GetRequestStream();
			do
			{
				DataRead = ReadIn.Read(FileData,0,2048);
				if (DataRead > 0) // We have data.
				{
					tempStream.Write(FileData,0,DataRead); 
					Array.Clear(FileData,0, 2048); // Clear the array.
				}
			}while(DataRead > 0);
	
			WResponse = (HttpWebResponse)WRequest.GetResponse(); 
			// Read your response data here.
			// Close all streams
			ReadIn.Close();
			tempStream.Close();
			WResponse.Close();
		}

public void test(Uri URL)
		{
			HttpWebRequest WRequest;
			HttpWebResponse WResponse;
			CredentialCache myCredCache = new CredentialCache();
			myCredCache.Add(URL,"NTLM",(NetworkCredential) CredentialCache.DefaultCredentials);
			// Pre-authenticate the request.
			WRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
			// Set the username and the password.
			WRequest.Credentials = myCredCache;
			// For NTLM authentication, you must set the following property to true
			// so the connection does not close.
			WRequest.UnsafeAuthenticatedConnectionSharing = true;
			WRequest.UserAgent = "Upload Test";
			WRequest.Method = "HEAD";
			WRequest.Timeout = 10000;
			WResponse = (HttpWebResponse)WRequest.GetResponse(); 
			WResponse.Close();
			// Make the real request.
			WRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
			// Set the username and the password.
			WRequest.Credentials = myCredCache;
			// For NTLM authentication, you must set the following property to true
			// so the connection does not close.
			WRequest.UnsafeAuthenticatedConnectionSharing = true;
			WRequest.UserAgent = "Upload Test";
			WRequest.Method = "POST";
			WRequest.AllowWriteStreamBuffering = false;
			WRequest.Timeout = 10000;
			FileStream ReadIn = new FileStream("c:\\ testuploadfile.txt", FileMode.Open, FileAccess.Read);
			ReadIn.Seek(0, SeekOrigin.Begin); // Move to the start of the file.
			WRequest.ContentLength = ReadIn.Length; // Set the content length header to the size of the file.
			Byte[] FileData = new Byte[ReadIn.Length]; // Read the file in 2 KB segments.
			int DataRead = 0;
			Stream tempStream = WRequest.GetRequestStream();
			do
			{
				DataRead = ReadIn.Read(FileData,0,2048);
				if (DataRead > 0) // We have data.
				{
					tempStream.Write(FileData,0,DataRead); 
					Array.Clear(FileData,0, 2048); // Clear the array.
				}
			}while(DataRead > 0);
	
			WResponse = (HttpWebResponse)WRequest.GetResponse(); 
			// Read your response data here.
			// Close all streams.
			ReadIn.Close();
			tempStream.Close();
			WResponse.Close();

		}