[RESOLVED] problem with code - sockets

hi guys
i am going through some msdn sample packages.

i am trying to connect to the tcpclient. ( chat program on sockets)

this works fine if i use "localhost" but i want this to connect over the internet

i am getting the error 'No such host is known'

VB Code:

Dim serverIP As IPAddress = ipaddress.Parse("X4.X5.XXX.36")
 
        client = New TcpClient("serverIP", PORT_NUM)

if anyone can see any possible problems please let me know,

so it looks correct then ?

I'd lose the quotation marks. :)

client = New TcpClient(serverIP, PORT_NUM)

yeah now the target machine is actively refusing the connection!!!

this is a nightmare lol

If the server isn't listening for connections and accepting it's not your code that's the problem it's the server you're trying to use.

yeah i think your right
i hate this kind of thing.
i know the code is probably most likely ok , but the settings on the pc' messes it up

If your code works on local host as a server it's probably the remote server thats the problem, does it work on localhost?

yeah it works on local host,
it doesnt work when i use the ip address though.
its really frying my brains lol

is there anyone who could guide me through the steps to resolve this

i am behind a router and i believe i have the port open

Quote:

---

An unhandled exception of type 'System.Net.Sockets.SocketException' occurred in system.dll

Additional information: No connection could be made because the target machine actively refused it

---

note client and server is on one machine

any ideas would be much appreciated as i have been trying to get this working a long time

If it works on local host but not with the router IP it must a problem with port forwarding. Check on your routers control panel that the port you use is being forwarded to the host which your running the server on.

Also can you upload all of your code, as you seem to have not declared PORT_NUM.

yeah i have declared PORT_NUM

i will go in and recheck, the router but i am like 100% sure the port is open and forwarded. - obviously not though
on the router my pc is addressed to
10.0.0.20

yes i have it set up as an inbound service

service is called chat

Details :
Chat(TCP/UDP:1828)
action - allow always
send to lan server - 10.0.0.20

note 1828 is the PORT_NUM i have declared in my code

EDIT: when i check attached devices on the router
10.0.0.20 is not there

it has never raised an issue before though

client code

VB Code:

Const READ_BUFFER_SIZE As Integer = 255
    Const PORT_NUM As Integer = 1828
 
    Private client As TcpClient
    Private readBuffer(READ_BUFFER_SIZE) As Byte
 
 
 
    ' Pop up a Connect user dialog and send a message requesting user to log in to chat.
    Sub AttemptLogin()
        Dim frmConnectUser As New frmConnectUser()
        frmConnectUser.StartPosition = FormStartPosition.CenterParent
        frmConnectUser.ShowDialog(Me)
        SendData("CONNECT|" & frmConnectUser.txtUserLogin.Text)
        frmConnectUser.Dispose()
    End Sub
 
    ' Clear the Users listbox, and request the server to send the list of users.
    Private Sub btnListUsers_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnListUsers.Click
        lstUsers.Items.Clear()
        SendData("REQUESTUSERS")
    End Sub
 
    ' Send the contents of the Send textbox if it isn't blank.
    Private Sub btnSend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSend.Click
        If txtSend.Text <> "" Then
            DisplayText("You say: " & txtSend.Text & Chr(13) & Chr(10))
            SendData("CHAT|" & txtSend.Text)
            txtSend.Text = ""
        End If
 
    End Sub
 
    ' Writes text to the output textbox.
    Private Sub DisplayText(ByVal text As String)
        txtDisplay.AppendText(text)
    End Sub
 
    ' This is the callback function for TcpClient.GetStream.Begin to get an
    ' asynchronous read.
    Private Sub DoRead(ByVal ar As IAsyncResult)
        Dim BytesRead As Integer
        Dim strMessage As String
 
        Try
            ' Finish asynchronous read into readBuffer and return number of bytes read.
            BytesRead = client.GetStream.EndRead(ar)
            If BytesRead < 1 Then
                ' If no bytes were read server has close.  Disable input window.
                MarkAsDisconnected()
                Exit Sub
            End If
 
            ' Convert the byte array the message was saved into, minus two for the
            ' Chr(13) and Chr(10)
            strMessage = Encoding.ASCII.GetString(readBuffer, 0, BytesRead - 2)
 
            ProcessCommands(strMessage)
 
            ' Start a new asynchronous read into readBuffer.
            client.GetStream.BeginRead(readBuffer, 0, READ_BUFFER_SIZE, AddressOf DoRead, Nothing)
        Catch e As Exception
            MarkAsDisconnected()
        End Try
    End Sub
 
    ' Send the server a disconnect message  
    Private Sub frmMain_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        ' Send only if server is still running.
        Try
            If btnSend.Enabled = True Then
                SendData("DISCONNECT")
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
     
    End Sub
 
    ' When the form starts, this subroutine will connect to the server and attempt to
    ' log in.
    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim frmConnectUser As New frmConnectUser()
 
        'Try
        ' The TcpClient is a subclass of Socket, providing higher level 
        ' functionality like streaming.
 
        'Dim hostName As String = System.Net.Dns.GetHostName()
        'Dim ipaddress As String = System.Net.Dns.GetHostByName(hostName).AddressList(0).ToString
        'Dim serverIP As IPAddress = IPAddress.Parse("localhost")
        'ipaddress = "84.45.225.63"
        'client = New TcpClient("serverIP", PORT_NUM)
        ' said local host
 
        'Dim serverIP As IPAddress = IPAddress.Parse("84.45.225.63")
        'client = New TcpClient(New IPEndPoint(serverIP, PORT_NUM))
 
        Try
            client = New TcpClient("84.45.225.63", PORT_NUM)
            ' Start an asynchronous read invoking DoRead to avoid lagging the user
            ' interface.
            client.GetStream.BeginRead(readBuffer, 0, READ_BUFFER_SIZE, AddressOf DoRead, Nothing)
 
            ' Make sure the window is showing before popping up connection dialog.
            Me.Show()
 
            AttemptLogin()
            'Catch Ex As Exception
            '   MsgBox("Server is not active.  Please start server and try again.", _
            '         MsgBoxStyle.Exclamation, Me.Text)
            ' Me.Dispose()
            'End Try
 
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
   
    End Sub
 
    ' This subroutine adds a list of users to listbox.
    Private Sub ListUsers(ByVal users() As String)
        Dim I As Integer
        For I = 1 To users.Length - 1
            lstUsers.Items.Add(users(I))
        Next
    End Sub
 
    ' When the server disconnects, prevent further chat messages from being sent.
    Private Sub MarkAsDisconnected()
        txtSend.ReadOnly = True
        btnSend.Enabled = False
    End Sub
 
    ' Process the command received from the server, and take appropriate action.
    Private Sub ProcessCommands(ByVal strMessage As String)
        Dim dataArray() As String
 
        ' Message parts are divided by "|"  Break the string into an array accordingly.
        dataArray = strMessage.Split(Chr(124))
 
        ' dataArray(0) is the command.
        Select Case dataArray(0)
            Case "JOIN"
                ' Server acknowledged login.
                DisplayText("You have joined the chat" & Chr(13) & Chr(10))
            Case "CHAT"
                ' Received chat message, display it.
                DisplayText(dataArray(1) & Chr(13) & Chr(10))
            Case "REFUSE"
                ' Server refused login with this user name, try to log in with another.
                AttemptLogin()
            Case "LISTUSERS"
                ' Server sent a list of users.
                ListUsers(dataArray)
            Case "BROAD"
                ' Server sent a broadcast message
                DisplayText("ServerMessage: " & dataArray(1) & Chr(13) & Chr(10))
        End Select
    End Sub
 
    ' Use a StreamWriter to send a message to server.
    Private Sub SendData(ByVal data As String)
        Dim writer As New IO.StreamWriter(client.GetStream)
        writer.Write(data & vbCr)
        writer.Flush()
    End Sub
End Class

Change

VB Code:

client = New TcpClient("84.45.225.63", PORT_NUM)

to

VB Code:

client = New TcpClient("10.0.0.20", PORT_NUM)

and see if it works. If it does it's a router problem, if it doesn't it's a problem with your code.

well then its a router problem because i know that works

what a noghtmare

Is 84.45.225.63 your public IP? The public IP of the computer you're running this code on? If so, your router probably doesn't do loopback. The only solution, if you have to have it work this way, is to replace the router with one that does loopback.

A router capable of loopback recognizes that the IP you're trying to reach is your own, so it just connects you to the internal address instead, 10.0.0.20 in this case. A router that doesn't do loopback looks on the WAN side for that IP and, since it can't see itself, it can't connect.

thanks Al42

so in your opinion, i could continue to devlop using my 10.0.0.20 on my development machine.

then when i move it out to deploy it (server on different fixd ip behind a different router). it should could work

It won't work if you use the server's private IP from outside the LAN. You'll have to forward the port in the router to the server and access the public IP from outside. If the router supports loopback you can access it from inside the LAN by using the public IP also, but if it doesn't you have to use the private IP from the LAN.