Problem with tcp server/client - Unable to write data

Hello guys, i've downloaded a tcp server with correspondent client and made some tests: On LAN and offline network works 100%, but when i use WAN, the server only receive 5~15 messages and crashes with the error "unable to write data to the transport connection an existing connection was forcibly closed". On cliente side the message isn't delivered to other users.

Server code:

Code:

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Imports System.Net.Sockets
Imports System.Text
Module Module1
    Dim clientsList As New Hashtable
    Sub Main()
        Dim serverSocket As New TcpListener(8888)
        Dim clientSocket As TcpClient
        Dim infiniteCounter As Integer
        Dim counter As Integer

        serverSocket.Start()
        msg("Chat Server Started ....")
        counter = 0
        infiniteCounter = 0
        For infiniteCounter = 1 To 2
            infiniteCounter = 1
            counter += 1
            clientSocket = serverSocket.AcceptTcpClient()

            Dim bytesFrom(1024) As Byte
            Dim dataFromClient As String

            Dim networkStream As NetworkStream = _

            clientSocket.GetStream()
            networkStream.Read(bytesFrom, 0, CInt(clientSocket.ReceiveBufferSize))
            dataFromClient = System.Text.Encoding.ASCII.GetString(bytesFrom)
            dataFromClient = _
            dataFromClient.Substring(0, dataFromClient.IndexOf("$"))

            clientsList(dataFromClient) = clientSocket

            broadcast(dataFromClient + " Joined ", dataFromClient, False)

            msg(dataFromClient + " Joined chat room ")
            Dim client As New handleClinet
            client.startClient(clientSocket, dataFromClient, clientsList)
        Next

        clientSocket.Close()
        serverSocket.Stop()
        msg("exit")
        Console.ReadLine()
    End Sub

    Sub msg(ByVal mesg As String)
        mesg.Trim()
        Console.WriteLine(" >> " + mesg)
    End Sub
    Private Sub broadcast(ByVal msg As String, _
    ByVal uName As String, ByVal flag As Boolean)
        Dim Item As DictionaryEntry
        For Each Item In clientsList
            Dim broadcastSocket As TcpClient
            broadcastSocket = CType(Item.Value, TcpClient)
            Dim broadcastStream As NetworkStream = _
                    broadcastSocket.GetStream()
            Dim broadcastBytes As [Byte]()

            If flag = True Then
                broadcastBytes = Encoding.ASCII.GetBytes(uName + " says : " + msg)
            Else
                broadcastBytes = Encoding.ASCII.GetBytes(msg)
            End If

            broadcastStream.Write(broadcastBytes, 0, broadcastBytes.Length)
            broadcastStream.Flush()
        Next
    End Sub

    Public Class handleClinet
        Dim clientSocket As TcpClient
        Dim clNo As String
        Dim clientsList As Hashtable

        Public Sub startClient(ByVal inClientSocket As TcpClient, _
        ByVal clineNo As String, ByVal cList As Hashtable)
            Me.clientSocket = inClientSocket
            Me.clNo = clineNo
            Me.clientsList = cList
            Dim ctThread As Threading.Thread = New Threading.Thread(AddressOf doChat)
            ctThread.Start()
        End Sub

        Private Sub doChat()
            Dim infiniteCounter As Integer
            Dim requestCount As Integer
            Dim bytesFrom(10024) As Byte
            Dim dataFromClient As String
            Dim sendBytes As [Byte]()
            Dim serverResponse As String
            Dim rCount As String
            requestCount = 0
            For infiniteCounter = 1 To 2
                infiniteCounter = 1
                Try
                    requestCount = requestCount + 1
                    Dim networkStream As NetworkStream = _
                            clientSocket.GetStream()
                    networkStream.Read(bytesFrom, 0, CInt(clientSocket.ReceiveBufferSize))
                    dataFromClient = System.Text.Encoding.ASCII.GetString(bytesFrom)
                    dataFromClient = _
                        dataFromClient.Substring(0, dataFromClient.IndexOf("$"))
                    msg("From client - " + clNo + " : " + dataFromClient)
                    rCount = Convert.ToString(requestCount)

                    broadcast(dataFromClient, clNo, True)
                Catch ex As Exception
                    MsgBox(ex.ToString)
                End Try
            Next
        End Sub

    End Class
End Module

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Client code:

Code:

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Imports System.Net.Sockets
Imports System.Text
Public Class Form1
    Dim clientSocket As New System.Net.Sockets.TcpClient()
    Dim serverStream As NetworkStream
    Dim readData As String
    Dim infiniteCounter As Integer

    Private Sub Button1_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click
        Dim outStream As Byte() = _
        System.Text.Encoding.ASCII.GetBytes(TextBox2.Text + "$")
        serverStream.Write(outStream, 0, outStream.Length)
        serverStream.Flush()
    End Sub

    Private Sub msg()
        If Me.InvokeRequired Then
            Me.Invoke(New MethodInvoker(AddressOf msg))
        Else
            TextBox1.Text = TextBox1.Text + Environment.NewLine + " >> " + readData
        End If
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button2.Click
        readData = "Conected to Chat Server ..."
        msg()
        clientSocket.Connect("ip", 8888)
        'Label1.Text = "Client Socket Program - Server Connected ..."
        serverStream = clientSocket.GetStream()

        Dim outStream As Byte() = _
        System.Text.Encoding.ASCII.GetBytes(TextBox3.Text + "$")
        serverStream.Write(outStream, 0, outStream.Length)
        serverStream.Flush()

        Dim ctThread As Threading.Thread = New Threading.Thread(AddressOf getMessage)
        ctThread.Start()
    End Sub

    Private Sub getMessage()
        For infiniteCounter = 1 To 2
            infiniteCounter = 1
            serverStream = clientSocket.GetStream()
            Dim buffSize As Integer
            Dim inStream(10024) As Byte
            buffSize = clientSocket.ReceiveBufferSize
            serverStream.Read(inStream, 0, buffSize)
            Dim returndata As String = _
            System.Text.Encoding.ASCII.GetString(inStream)
            readData = "" + returndata
            msg()
        Next
    End Sub
End Class

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What i need to do to fix this?

Ty all

There's quite a bit of code there and you've given no indication that you've done any real investigation yourself, i.e. debugging to narrow down exactly where the error occurs and what data is in use at the time. You should be able to provide a specific set of steps that we can perform to reproduce the issue and an explanation of exactly what we should expect. As it is, I'm not inclined to make the effort required to narrow down the issue first and then try to fix it and I suspect that many others won't either. You should do everything you can to help us help you or you're less likely to get help at all.

Quote:

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Originally Posted by jmcilhinney

There's quite a bit of code there and you've given no indication that you've done any real investigation yourself, i.e. debugging to narrow down exactly where the error occurs and what data is in use at the time. You should be able to provide a specific set of steps that we can perform to reproduce the issue and an explanation of exactly what we should expect. As it is, I'm not inclined to make the effort required to narrow down the issue first and then try to fix it and I suspect that many others won't either. You should do everything you can to help us help you or you're less likely to get help at all.

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I tried 3 different methods, debugged and the problem persist... On google this problem was ony solved to asp.net
How to reproduce the issue: Just start the server and use the client to connect using external ip. Afeter 5~15 messages, the server closes and appear the error message (unable to write/read data to the transport connection an existing connection was forcibly closed by the server).
I need to know how the server can keep the connections :/

I forgot the screenshots:
What happened: i started the server, and connected with client, after 15 seconds, returned the error