[2008] Basic TCP Communication

Ive been wanting to create a simple Server-Client programs and Ive searched the net alot, but all the coding online are very complex for a newbie. So Atheist helped me code a simple TCP communication program
The original topic is
http://www.vbforums.com/showthread.php?t=502795

Attached is the Server code and Client code
have fun

thanks

thnx

Remember: TCPListener only listens on LOCAL IP.

If your using a router, or a modem that assigns your computer a local IP then you must do the following:

A scenario:

Say your server on your computer listens to port 43001 on your local IP.

Your client on another computer tries to connect to your WAN IP but throws an exception becuase the computer did not respond in a timely manner.

What you should do:

Since your listening to port 43001 on local IP (ex: 192.168.2.1), you must forward ports.

You must forward the same port from your router to your local IP. For example
if I am connecting to 43.11.14.50 port 43001. I must do:

forward 43.11.14.50:43001 -> 192.168.2.1: 43001.

Make sure your firewall allows these ports to go through.

ALSO OPENING PORTS IS VERY DANGEROUS. YOU SHOULD RESEARCH INTO PROPER SECURITY IF YOUR DOING THIS!

Very nice, thanks for the sample code!

Thanks alot Have nice day

Hi,

Just seems to stick on finding an Ident... until it pings out:(

Could you elaborate on your problem? Perhaps post a code snippet of what is causing it?

This code is exactly what I was after thank you.
One small thing though, the client app sends a message saying /DISCONNECT before it disconnects, which fires an event on the server. Is there anyway to have the server fire an event when a client leaves, without needing the client to send a message?

Thanks

brilliant code, thanks heaps, I'm sure plenty of people will benefit from this

what if you want to stop listener? I mean if the user wants to change username or port?

This is where you start to listen from clients:

listener = New TcpListener(IPAddress.Any, txtPort.Text)
listener.Start() 'Start listening.
listenThread = New Thread(AddressOf DoListen)
listenThread.IsBackground = True
listenThread.Start()

And here's the DoListen

Private Sub DoListen()
Dim incomingClient As System.Net.Sockets.TcpClient
Do
incomingClient = listener.AcceptTcpClient
Dim connClient As New ConnectedClient(incomingClient, Me)
AddHandler connClient.dataReceived, AddressOf Me.MessageReceived
clients.Add(connClient) 'Adds the connected client to the list of connected clients.
Me.MessageReceived
Loop
End Sub

How do you stop listener? I tried doing this but I always get an error:

listener.Stop()
listenThread.Abort()

hi

please share Solution for newbie like me for this.. you will help me a lot if you share

Im having a problem creating Design ....

when i have pasted to my form1.vb the whole codes for server theres a lot of red line even created a design

'We have
'4 textboxes txtSend, txtUsername, txtPort, txtMain (txtMain is multiline and readonly)
'lblConnection
'btnListen, btnSend, btnSendAll
'listbox lbClients

but on client it was ok.. help

Thanks for example,
but i two problems:

1. When I want to send every message from every client to all connected clients (multiusers chat) I try with this:

Code:

---

  For Each cc As ConnectedClient In clients
                    cc.SendMessage(receivedString)
                Next

---

but problem is because when is connected 10-12 peoples and writing to much sometime happend that two, or more messages going in one LINE.
For example, if I send "test", my friend 1 send "test2" its showing like this:
stefanACM: testfriend1: test2
How to solve that ???

2. What is easiest way to transfer CLIENT LIST to every client ?


Thanks in advice

Any one ?

Hey i have been playing around with this code in VB .net 2010 and its really cool,

RE: You would might need to add & vbcrlf to the end here:

For Each cc As ConnectedClient In clients
cc.SendMessage(RecievedString & vbcrlf)
Next
:D

hope it helps

I'm a newbie to VB 2010 Express and I just wanted to say a :thumb:huge thank you to both :wave:Atheist and :wave:perito for your threads on Basic TCP Communication.

I had a small project where I wanted to download trace data from an RF spectrum analyzer and place it into a .CSV file for analysis. Your comments, tutorials and examples have proved invaluable to me. My little project has been a success!

Thanks so much!

How send a message from server to client? I cannot make it work proprely.

how can i turn this code into a messenger? :D as in multiple ppl sending message to each other? do i need to send the message to the server thn to the client?
for example

Client 1 to Client 2

would be like C1 to S thn S to C2

right?

Quote:

---

Originally Posted by masfenix

Remember: TCPListener only listens on LOCAL IP.

If your using a router, or a modem that assigns your computer a local IP then you must do the following:

A scenario:

Say your server on your computer listens to port 43001 on your local IP.

Your client on another computer tries to connect to your WAN IP but throws an exception becuase the computer did not respond in a timely manner.

What you should do:

Since your listening to port 43001 on local IP (ex: 192.168.2.1), you must forward ports.

You must forward the same port from your router to your local IP. For example
if I am connecting to 43.11.14.50 port 43001. I must do:

forward 43.11.14.50:43001 -> 192.168.2.1: 43001.

Make sure your firewall allows these ports to go through.

ALSO OPENING PORTS IS VERY DANGEROUS. YOU SHOULD RESEARCH INTO PROPER SECURITY IF YOUR DOING THIS!

---

this was very helpful
I knew the code for local IPs but I hadnt any information about forwarding
really helped:bigyello:

I'm attempting to run this in VS 2012 Express....but the server is showing 58 errors and the client is showing 50 errors. Is this just not compatible with VS 2012 or should I keep trying?