An existing connection was forcibly closed by the remote host (3 replies)

Hi,

We are using an in house written WPF application which uses .Net Connector 6.3.4. The MySql database is running on SBS 2011 Standard.

Problem Description
The application has been working fine for months but starting last week we started to get a problem whereby people working externally could no longer open a connection to the database. To be more specific only one external user at a time could connect, numerous users were connected fine from within the domain.

The exeption occurrs on the Open
MySqlConnection conn = new MySqlConnection(SerGlobals.ser_connection);
conn.Open();

Exception : Reading from the stream has failed.
Inner Exception : Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.

Detailed Execption:
MySql.Data.MySqlClient.MySqlException (0x80004005): Reading from the stream has failed. ---> 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 MyNetworkStream.HandleOrRethrowException(Exception e)
at MyNetworkStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.TimedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.BufferedStream.Read(Byte[] array, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.Open()
at MySql.Data.MySqlClient.Driver.Open()
at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
at MySql.Data.MySqlClient.MySqlPool.GetConnection()
at MySql.Data.MySqlClient.MySqlConnection.Open()
at MySqlTest.MainWindow.test_Click(Object sender, RoutedEventArgs e) in D:\Development\c#\MySqlTest\MySqlTest\MainWindow.xaml.cs:line 40MySql.Data.MySqlClient.MySqlException (0x80004005): Reading from the stream has failed. ---> 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 MyNetworkStream.HandleOrRethrowException(Exception e)
at MyNetworkStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.TimedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.BufferedStream.Read(Byte[] array, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.Open()
at MySql.Data.MySqlClient.Driver.Open()
at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
at MySql.Data.MySqlClient.MySqlPool.GetConnection()
at MySql.Data.MySqlClient.MySqlConnection.Open()
at MySqlTest.MainWindow.test_Click(Object sender, RoutedEventArgs e) in D:\Development\c#\MySqlTest\MySqlTest\MainWindow.xaml.cs:line 40
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 MyNetworkStream.HandleOrRethrowException(Exception e)
at MyNetworkStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.TimedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.BufferedStream.Read(Byte[] array, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()MySql.Data.MySqlClient.MySqlException (0x80004005): Reading from the stream has failed. ---> 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 MyNetworkStream.HandleOrRethrowException(Exception e)
at MyNetworkStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.TimedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.BufferedStream.Read(Byte[] array, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.Open()
at MySql.Data.MySqlClient.Driver.Open()
at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
at MySql.Data.MySqlClient.MySqlPool.GetConnection()
at MySql.Data.MySqlClient.MySqlConnection.Open()
at MySqlTest.MainWindow.test_Click(Object sender, RoutedEventArgs e) in D:\Development\c#\MySqlTest\MySqlTest\MainWindow.xaml.cs:line 40MySql.Data.MySqlClient.MySqlException (0x80004005): Reading from the stream has failed. ---> 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 MyNetworkStream.HandleOrRethrowException(Exception e)
at MyNetworkStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.TimedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.BufferedStream.Read(Byte[] array, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.Open()
at MySql.Data.MySqlClient.Driver.Open()
at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
at MySql.Data.MySqlClient.MySqlPool.GetConnection()
at MySql.Data.MySqlClient.MySqlConnection.Open()
at MySqlTest.MainWindow.test_Click(Object sender, RoutedEventArgs e) in D:\Development\c#\MySqlTest\MySqlTest\MainWindow.xaml.cs:line 40
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 MyNetworkStream.HandleOrRethrowException(Exception e)
at MyNetworkStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.TimedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.BufferedStream.Read(Byte[] array, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count)
at MySql.Data.MySqlClient.MySqlStream.LoadPacket()
System.Net.Sockets.SocketException (0x80004005): 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)

This is the first connection attempt by our software.

Using a network monitoring tool (Wireshark) I can see the successful connection coming through with all the expcected flags, data etc.
TCP [SYN]
TCP [ACK]
MySQL Login Request

But on the failed connection I can see the following :
TCP [SYN]
TCP [ACK]
TCP [RST]

I have also tried using Telnet, and MySQL Workbench and both fail if there is already an external connection, i.e. from outside the domain.

Can anyone help with his, I have been banging my head against brick wall for the last week trying to resolve this.

Thanks,

Steve Perrins