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Introduction to TCP/IP
Sockets
The previous sections described what information a program needs to communicate over a TCP/IP network. The next step is for the program to create what is called a socket, a communications end-point that can be likened to a telephone. However, creating a socket by itself doesn’t let you exchange information, just like having a telephone in your house doesn’t mean that you can talk to someone by simply taking it off the hook. You need to establish a connection with the other program, just as you need to dial a telephone number, and to do this you need the socket address of the application that you want to connect to. This address consists of three key parts: the protocol family, Internet Protocol (IP) address and the service port number.
We’ve already talked about the IP address and service port, but what’s the protocol family? It’s a number which is used to logically designate the group that a given protocol belongs to. Since the socket interface is general enough to be used with several different protocols, the protocol family tells the underlying network software which protocol is being used by the socket. In our case, the Internet Protocol family will always be used when creating sockets. With the protocol family, IP address of the system and the service port number for the program that you want to exchange data with, you’re ready to establish a connection.
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hi
This is possible using threads in the client program. the client can generate parallel connections using threads. so u can create multiple clients in the same system.
In the server side, you use two sockets. One for receive the data and another for response to corresponding clients. Use the FDSET, FDISSET functions to achieve this apps. This is reliable one
Hope I may answered your question.
Karthik
hi i want to make socket connection for the multiple clients like i want to send the data to the server to the multiple clients how i will be able to do that. IS there anybody else who can help me. I am able to do that by socket programming but only in single system when i want to do that on multiple system then it is not possible.is there any one? its very needed.................................... thanks and bye
Hi,
Iam developing the socket application.In this the remote host is sending messages.But iam not able to pick all the messages sent by the remote host.If remote is sending 10 msgs,then iam able to pick 2 or 3 msgs.pls tell me,what could be the reason for that asap.
Thank you.
i m sending this code asuming that u have some prior knowledge about network programming
include this code at server side
Private Sub listen_Click()
Winsock1.LocalPort = 1002
Winsock1.listen
End Sub
Private Sub cmdsend_Click()
Winsock1.SendData chattxtbox.Text
txtwindow.Text = txtwindow.Text & vbNewLine & chattxtbox.Text
chattxtbox.Text = ""
txtwindow.SelStart = Len(txtwindow)
End Sub
Private Sub Winsock1_ConnectionRequest(ByVal requestID As Long)
Winsock1.Close
Winsock1.Accept requestID
End Sub
Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long)
Dim txtwindowdata As String
Winsock1.GetData txtwindowdata
txtwindow.Text = txtwindow.Text & vbNewLine & txtwindowdata
txtwindow.SelStart = Len(txtwindow)
End Sub
//include this one at client siderivate Sub cmdconnect_Click()
Winsock1.RemoteHost = "127.0.0.1"
Winsock1.RemotePort = 1002
Winsock1.Connect
End Sub
Private Sub cmdsend_Click()
Winsock1.SendData chattxtbox.Text
rectxtwindow.Text = rectxtwindow.Text & vbNewLine & rectxtwindow.Text
chattxtbox.Text = ""
End Sub
Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long)
Dim txtfromserver As String
Winsock1.GetData txtfromserver
rectxtwindow.Text = rectxtwindow.Text & vbNewLine & txtfromserver
rectxtwindow.SelStart = Len(rectxtwindow)
End Sub
Private Sub Winsock1_Connect()
MsgBox "Connecting to Server....Plz stay far n WAIT"
End Sub
this will make a client server chat applicatin with in a LAN
Hi. I read ur message. I'm doing a (socket programming) chatty client/server messenger program too and I need lots of help. I heard you have done it. Could u send me ur source code and i could refer to it. Thanks alot it will help me greatly. By the way i'm using tcp.
example:
for each.. blah blah
Winsock1.SendData blah
DoEvents
end for
Hi...
im new to tcp programming using winsock control in Vusual Basic.
i tried a client server chat program, in which there is a client program running and its
communicting with a server program. when i tried with two clients communicating thru a server program..its not working...can you help me....please send the source code also..
By
Faisal
I only speak a lite bit of English
I need to know the name of the file on Windows to define a
new LocalPort (UDP port) for a new application (Client/Server) of
Files.
Mi lenguaje es el Castellano.
Thanks Javier
If you're using SocketWrench, there's an HTTP client and server example that's included that could probably serve as a foundation for what you're interested in doing. If you have any specific questions, I'd be happy to answer them for you.
I am a new member and my question might have been asked before but i can not find it in the archives.
But if anyone would be able to help, please do. I would be greatful.
Q: I have to create a (http like) protocol to enable the client communicate with a server. I know the basics but would be greatful for any ideas. Thanks
How are you broadcasting? Are you using TCP/IP or UDP? I have sent broadcast messages using UDP just by using the broadcast address 255.255.255.255 so that the packet goes everywhere. I had problems prior to using this when the PC's were in different domains. I dont know if this helps!
i created a client/server application using winsock, and everything works fine except if i try to send a message to all the clients from the server, only the last client actually recieves the message. after much research i found the service pack 4 for VB resolves this issue...but it only resolved the issue if i use my computer (that has VB) as the server.... i need to use a computer that does not have VB to be the server. Can anyone help me!!!!!
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