need socket help

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shingo99

Freshman
Joined
Jul 19, 2004
Messages
31
hello
i have develop a server-client chat room using VB.Net
some how i only can make the client connect the server if i open it on the same computer
when i try to connect it using my laptop (server on desktop) all i get is "Cannot connect server"
this program connection is using port.
can i use IP address or computer name at my client to detect the server?
can teach me how to connect to the server please
thank you in advance

p.s if there is no way to connect/detect the server this way please tell me so that i can change my programming title
 
Could you post your existing code - it makes it easier to troubleshoot if we can see what is going on?

How are you currently connecting to the server from the client?
 
PlausiblyDamp said:
Could you post your existing code - it makes it easier to troubleshoot if we can see what is going on?

How are you currently connecting to the server from the client?
Click to expand...

ok here is the current code i have
on the client side
'connect to server
Private Sub connect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles connect.Click
If portbox.Text <> "" Then
chatbox.AppendText("Requesting Connection..." & vbCrLf)
On Error GoTo err
myclient = New TcpClient(portbox.Text)
myclient.GetStream.BeginRead(mydata, 0, 1024, AddressOf DoRe, Nothing)
Status1.Panels(0).Text = "Requesting Connection..."
chatbox.AppendText("Connected..." & vbCrLf)
Status1.Panels(0).Text = "Connected to :" & portbox.Text
Timer1.Enabled = True
a = InputBox("Enter Nickname:")
Send("nick:" & a)
ipbox.Enabled = False
portbox.Enabled = False
Button1.Visible = False
sendbox.Enabled = True
Button4.Visible = True
End If
err: If sendbox.Enabled = False Then
chatbox.AppendText("Unable to resolve to Server...Please try again")
End If
End Sub

'read data from server
Private Sub DoRe(ByVal ar As IAsyncResult)
Dim intCo As Integer

Try
intCo = myclient.GetStream.EndRead(ar)
If intCo < 1 Then
chatbox.AppendText("Disconnected" & vbCrLf)
Exit Sub
End If

BuildString(mydata, 0, intCo)

myclient.GetStream.BeginRead(mydata, 0, 1024, AddressOf DoRe, Nothing)
Catch e As Exception
End Try
End Sub

and here is the server side
'open the server n port
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
On Error Resume Next
myport = InputBox("Enter Port:", "Port Settings")
myThread = New Thread(AddressOf DoList)
myThread.Start()
UpdateStatus("Server Active on port:" & myport)
End Sub
'start listen for clients
Private Sub DoList()
Try
myListener = New TcpListener(myport)
myListener.Start()
Do
Dim q As New Client(myListener.AcceptTcpClient)
AddHandler q.Connected, AddressOf OnConnected
AddHandler q.Disconnected, AddressOf OnDisconnected
AddHandler q.LineReceived, AddressOf OnLineReceived
myClients.Add(q.ID, q)
Loop Until False
Catch
End Try
End Sub
i hope you can help me
thank you
 
In the client code you need to modify the line
Visual Basic: 
myclient = New TcpClient(portbox.Text)
to include the address of the server you need to connect to

i.e.
Visual Basic: 
myclient = New TcpClient(serverbox.Text, portbox.Text)

where serverbox is another textbox on the form allowing a user to enter the servers name or address.
 
serverbox created but still not working
myclient = New TcpClient(serbox.Text, portbox.Text)
and i notice that this coding is always underline(error indication)
myListener = New TcpListener(myport)

i been thinking.. can i set the IP or the computer name of my desktop so that my client can connect the server directly through both port and IP/name or the coding is already working
i ask some of my friends and they say it could be the reason of firewall on both of my computer since im not the administrator, just a guest user
could this be the problem?
im asking this cause later the users of the application wont be administrator of the computer, so the aplication must be able to be used by guests
sorry for the trouble and thank you
 
Last edited:
When you say it still isn't working what errors do you get? What are you putting into the serverbox field (ip address of remote server, server name etc.)?

Also when you say the line
Visual Basic: 
myListener = New TcpListener(myport)
has the error indicator on it if you hold your mouse over the line what error appears in the tooltip?

As to the other ideas: is there a firewall between you and the other computer?
 
there is no error.. it just cant detect my server
normally if connected it will just say "Connected to server" else it will say "Cannot connect to server"
and "Cannot connect to server" is what it say on the textbox

while on the serverbox i put "localhost" and on the portbox i put "8080"
at the server i put the port as "8080" as default
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
On Error Resume Next
myport = 8080
myThread = New Thread(AddressOf DoListen)
myThread.Start()
UpdateStatus("Server Active on port:" & myport)

End Sub
as i say before my server run on ports cause this is all i know
i didnt learn about connection using IP
most of the coding i got from book that is available in library

as for the error myListener = New TcpListener(myport)
it say
"public sub new (port as integer) is obsolete: use TcpListener(IPAddress localaddr, int port)"

now im manage to get the administrator password and im using it and yes there is a firewall between my desktop and the laptop
thank you for your help
 
If you put localhost into the serverbox field and run the server locally does it connect? If so things are still okay.
If you run the server remotely and put the server's name or ip address in serverbox does it now fail to connect?
If there is a firewall between the two boxes then this is probably blocking access to certain (most) ports and will prevent connection - you will need to either convince the network administrator to open the relevant port (may be hard to convince though) or try and run the server and client portions of the project on two machines without a firewall between them.

The warning you are getting about
Visual Basic: 
myListener = New TcpListener(myport)
simply means that this is no longer the recomended way to setup a listner and this may not be supported in a future version of the framework.
You should probably use the following code instead
Visual Basic: 
myListner= New TcpListner(IPAddress.Any,myport)
 
ok the firewall is off but still not working
locally?
if you mean the server and the client on the same computer then yes it is working prefectly
but if you mean in local LAN (2 computers joining) then no
the server is always open but the only problem is that the client on laptop cannot "ping" the server on my desktop
i try opening the server on laptop and client on desktop and the result is the same
the client can only ping the server if it is in the same computer as the server

i have try the code modification
myListner= New TcpListner(IPAddress.Any,myport)
but still nothing

ok here is the summary of the current status
LAN connection clear
firewall off
server on
client cant ping server
thank you again for your help
 
PlausiblyDamp said:
What is the IP address and subnet mask of both the client and server?
Click to expand...
what do you mean by subnet mask??

IP address in my coding??
i didnt put any
i just import some file
Imports System.Threading
Imports System.Net
Imports System.Net.Sockets
Private myThread As Thread
Private myListener As TcpListener
and this is all im using to connect

IP address for the LAN connection?
in both my laptop and desktop i have set the networking to the same proxy IP n port are the same
or did i do something wrong (internet option->LAN setting->Proxy server then address="127.82.0.1" port="8080")

any problem with the LAN setting?i set both to the same thing
 
If you bring up a command prompt and type ipconfig it should tell you your TCP/IP address and subnet mask.
If you could do that on both the client and server what are the values for ip address, subnet mask and default gateway?

Setting a proxy server wouldn't really help as that will only be used by IE for access to the internet.
 
PlausiblyDamp said:
If you could do that on both the client and server what are the values for ip address, subnet mask and default gateway?
Click to expand...

ok im quite confuse here
both my client and server means....
i type ipconfig on my desktop so i just want to know should it be the same value as in both laptop and desktop?
i got my IP , submask value but gateway is null
 
Gateway being empty is fine, you need the server and client to be configured with ip addresses that can comunicate - given that you cannot ping this seems unlikely.
The client and server should not have the same ip address, but it does need to be within the same network range.
Without understanding how networks or TCP/IP work will make writting any network software tricky. You may find the following links worth a read as they do explain a bit more of the basics.
http://www.wown.com/j_helmig/tcpip.htm
http://www.yale.edu/pclt/COMM/TCPIP.HTM
http://www.pcsupportadvisor.com/search/c04100.htm
 
ok thanks
so now all i have to do is
set the client to detect the server IP
that is provided after i type IPCONFIG in the command prompt
so that my client can communicate with the server using the desktop(server) IP address
am i correct?
 
yes it does connect
thank you so much for your help
can i know how to detect my computer IP via VB.Net coding?
if there is none then is fine.
cause i just want to display it out to make thing easier for other user to know the server IP address
thank you again for your help
 
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