No connection could be made because the target machine actively refused it 127.0.0.1:101

Question

Hi All,

         I was trying out the exmaple application for a chat application given in http://msdn.microsoft.com/en-us/library/aa478452.aspx
but  i keep get the exception as below no matter what which port i specify, i even turned off the firewall  

System.Net.Sockets.SocketException was unhandled
  ErrorCode=10061
  Message="No connection could be made because the target machine actively refused it 127.0.0.1:101"
  NativeErrorCode=10061
  Source="System"
 
please help me out because i have use this application in my application

Regards
Archana Muralidhar

---

achu

Answer 1

Hi Archana,

Things you could check,


Ensure that your server application is running,

from the run menu type cmd to open a command prompt,
    
Type NETSTAT -A to check that your server application is listening on the port you specify.

Try running telnet to see if you can get a connection to your server application, worth a try.

Regards

Tony

Answer 2

even when i try running the server i am getting the same exception

---

achu

Answer 3

Are you getting the exception when you try to connect from the client app or are you getting the exception when you start the server app?

Regards

Tony

Answer 4

i am getting the same exception with both i.e. when trying to connecting to the server or when try to strat the server

---

achu

Answer 5

 

OK Archana,

 

In your form load event try this code, I managed to simulate your error using the MSDN code.  I also switched my windows firewall off.
I had to force the connection by calling connect directly after creating the TcpClient. 

Let me know if this works for you, This is code for the server app form load event. :)  You will want to tidy the code a bit it's a little messy :)

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try

            ' Get server related information.
            Dim heserver As System.Net.IPHostEntry = Dns.GetHostEntry("localhost")
            Dim curAdd As IPAddress
            For Each curAdd In heserver.AddressList
                
                Try
                    Dim ipE As New IPEndPoint(curAdd, 5000)
                    mobjClient = New TcpClient(ipE)
                    mobjClient.Connect("127.0.0.1", 5000)
                    If (mobjClient.Connected) Then
                        Exit For
                    End If
                Catch ex As Exception

                End Try

            Next

            If (mobjClient.Connected) Then
                DisplayText("Connected to host" & vbCrLf)
                mobjClient.GetStream.BeginRead(marData, 0, 1024, AddressOf DoRead, Nothing)
                Send("New client online")
            End If

        Catch ex As Exception
        End Try

    End Sub

Answer 6

 Hi Tony

        I am getting the following Exception



     System.Net.Sockets.SocketException was caught
  ErrorCode=10057
  Message="A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using a sendto call) no address was supplied"
  NativeErrorCode=10057
  Source="System"
 

---

achu

Answer 7

I have updated my code to reflect the following, and this works to a degree, the only problem is the lblstatus wont update so I threw a try catch round that.


Run the server app first and then the client app and you should get a connection.

The DoListen Sub of the server app

  Private Sub DoListen()
        Try

            Dim localAddr As IPAddress = IPAddress.Parse("127.0.0.1")
            Dim ipLocalEndPoint As New IPEndPoint(localAddr, 5000)
            mobjListener = New TcpListener(ipLocalEndPoint)

            mobjListener.Start()
            Do
                Dim x As New Client(mobjListener.AcceptTcpClient())
                AddHandler x.Connected, AddressOf OnConnected
                AddHandler x.Disconnected, AddressOf OnDisconnected
                AddHandler x.LineReceived, AddressOf OnLineReceived

                mcolClients.Add(x.ID, x)
                Dim params() As Object = {"New connection"}
                Me.Invoke(New StatusInvoker(AddressOf Me.UpdateStatus), params)
            Loop Until False
        Catch
        End Try
  End Sub

The form load event of the client app

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try

            ' Connect to the server
            mobjClient = New TcpClient("127.0.0.1", 5000)

            If (mobjClient.Connected) Then
                DisplayText("Connected to host" & vbCrLf)
                mobjClient.GetStream.BeginRead(marData, 0, 1024, AddressOf DoRead, Nothing)
                Send("New client online")
            End If

        Catch ex As Exception
        End Try

    End Sub


In the server App I had to throw a try cqtch round the update as there is a threading issue.

    Private Sub UpdateStatus(ByVal t As String)
        Try
            lstStatus.Items.Add(t)
            lstStatus.SetSelected(lstStatus.Items.Count - 1, True)
        Catch ex As Exception
        End Try
    End Sub

Answer 8

Hi Tony

       Yes this works, something imilar i have done, but one problem is that the message gets broadcasted to every on who are connected is there a way where in it can be intended to a particular person on the LAN

Regards
Archana Muralidhar

---

achu

Answer 9

 I believe you will need to play around with this bit of code in the server app.

  Private Sub OnLineReceived(ByVal sender As Client, ByVal Data As String)
    UpdateStatus("Line:" & Data)

    Dim objClient As Client
    Dim d As DictionaryEntry

    For Each d In mcolClients
      objClient = d.Value
      objClient.Send(Data & vbCrLf)  'this is where it send to all clients.  This will need to be filtered to only send to who you want it to.
    Next
  End Sub

You could possibly put a property in the client class that holds the ip address of the client. 

Kind Regards

Tony

Answer 10

Thank you Tony please be in touch i will ge back if i face any problem as i am new to Socket programming

---

achu