I have this code to connect to my server:
client = New TcpClient(txtIP.Text, txtPort.Text)
client.GetStream.BeginRead(readBuffer, 0, BYTES_TO_READ, AddressOf DoRead, Nothing)
SendMessage("/CONNECT|" & Label25.Text)
[code].....
I am trying to build a sort of basic server thing and I cannot seem to get the thing to work properly. I have a client and a server. The client sends a string, the server receives then replies. I cannot get the server to continue responding.
It works in one direction Client -> Server
But because the server is continuously listening the form becomes not responding, thus I cannot send messages from the server. Although it says that its not responding I know that it is just using all of the processing for listening because when I send something from the client the server responds, just the form is stuck because of the listener.
I have this code to connect to my server:
client = New TcpClient(txtIP.Text, txtPort.Text)
client.GetStream.BeginRead(readBuffer, 0, BYTES_TO_READ, AddressOf DoRead, Nothing)
SendMessage("/CONNECT|" & Label25.Text)
How do I check if the TcpListener is available?
I am using this function to get web page page source to my textbox.
Code:
Public Function OpenURL(ByVal strURL As String) As String
Dim client As New System.Net.WebClient
Dim data As System.IO.Stream = client.OpenRead(strURL)
Dim reader As New System.IO.StreamReader(data)
Dim s As String = reader.ReadToEnd()
[Code]...
Where to start for making a quick routine to check current download/upload speeds? I do have a web server I could download from but need some info on where to start?
View 1 RepliesI am using VB2008 Express and am curious how to send a command via RS232 communications. The string that I need to send is 02h PON 03h. The start and end bits are 02h and 03h.
How can I convert 02h and 03h to its ascii form. In hyperterminal, I use the sequence {(hold)ALT 0 0 2} on the number pad to send the start bit.
I am using this code currently without the start and end bits
Code:
I am creating an application that will be talking over the LAN (and eventually, WAN) which uses the Tcplistener and Tcpclient objects.Now, I have this working absolutely fine locally using the loopack address although when I change the IP of the listener to 0.0.0.0 (listening for all IPs) and the IP in the client application, to the IP of the server, it throws an exception when connecting. The client says something along the lines of the the server has rejected the incoming connection. So i disabled all firewalls temporarily but I still have the problem.I have ran netstat on the server which clearly shows that it is listening for an incoming connection on 0.0.0.0. [code]
View 5 RepliesHow do I free an instance of TcpListener?
How, in VisualBasic, to I delete something from a 'new'?[code]...
I have an application that listens for connections asynchronously. When a connection comes in, it spawns a new thread from the callback method. This works fine for up to about 13 simultaneous connections then it dies with an out of memory error. The threads that are spawned just do a CHAP handshake and authenticate then go in to a command loop where they sleep until a command comes in or a timeout occurs. I have pasted the code below. Sometimes it will not throw an error but the thread never gets spawned although the connection is accepted.
Code:
Imports System.Net.Sockets
Imports System.Threading
Public Class UpdateMonitor
[Code]....
I have just created a website server with Visual Basic 2008. I want my server to have the famous "resume donwload" function... but i dont know how the HTMLHeader should look like when its resuming a download.
Here is how the header normaly looks:
HTMLHeader = _
"HTTP/1.0 200 OK" & ControlChars.CrLf & _
"Server: Website Server " & My.Application.Info.Version.ToString & ControlChars.CrLf & _
"Content-Length: " & GetFileSize & ControlChars.CrLf & _
"Content-Type: " & GetContentType(StringRequest) & _
ControlChars.CrLf & ControlChars.CrLf
How can I detect when a client disconnects from the TcpListener ?
Each of my clients is handled in a separate thread.
Is it necessary to close the connection of a tcplistener or tcpclient after every message received, or is it possible to close it at a later time while it continues to receive data? Is there any major security issue with leaving it open and listening? I know trojans tend to open a listener and leave it open, will my program be detected as such? Its just a simple chat program....
View 1 Replies[code]I send the Thread via Thread.Sleep to sleep mode when nothing happens here. Does this affect the TCPListener in his work somehow and what happens to an incomming connection while the Thread is in sleep-mode?
View 3 RepliesI have been programming a TcpListener Program and I have everything working right! So far... Except that when I have multiple clients connecting to my Server... I used a try catch statement to catch the error and it says that tcplistener doesn't allow multi connections... think creating a new thread for each connection sounds like the most reasonible answer but I can't grasp the concept of it...
Here is my frmMain:
Imports System.IO
Imports System.Net
[code].....
I posted this code in another thread as an example of how to listen for connecting clients using TcpListener.it is a small part of a larger project, its all my own work,
Imports System.Net
Imports System.Net.Sockets
Public Class Server[code].....
How can I ask my tcpListener to listen to particular IP on specific port? I want my tcpListener to listen to the local IP of the machine. I can get the ipaddress of the pc using Dns.GetHostAddresses(). But, if pc have multiple ip's how can I know which ip address is correct? From tcpClient class I am connecting to the server. So, I know the server ip and so I want to specify ipaddress to my tcpListener class to listen on.
View 1 RepliesI am creating a simple program. (soon to be vastly complex) that is connecting to a server, and sending an authentication code to connect. I got the connection part, but what keeps breaking up is the method of authenticating. I have the entire authentication process in a while loop, so that it will keep going until it receives the authentication reply from the server (an OK-002938, or what ever client number the server decides.
This is my client code for the event:
Private Sub CONNECTSERVER_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles CONNECTSERVER.DoWork
Try
If network_client.Connected = False Then
network_client.Client.Connect(My.Settings.service_address.ToString, My.Settings.service_port.ToString)
[Code] .....
The client side is flawless. But the server side, works, but it doesn't continue past storing the bytes into a container...
I have a class that inherits from the TcpListener, this class Shadows the Start method just to call the base Start() and the base BeginAccept Tcp Client(). From time to time the method is called but the port is not opened (netstat does not show the port open).[code]The class that uses the ExtendedTcpListener implements the IDisposable pattern and inside the Dispose the ExtendedTcpListener.Stop is called.The stop text is not present at the logs when the problems happens.
View 4 RepliesI am working on a remote administration tool. But I have a problem, since the server connects to the client the client needs a tcplistener. But when the client starts too listen the program freezes and I can't do anything. The reason is that the tcplistener runs in a loop which freezes the form. What shall I do too fix the program?
View 1 RepliesBasically, in my Tcp Library I'm working on, whenever the system is told to "Stop", the OnClientConnected() Routine fires off, which is only raised under two circumstances: When a Client connects (obviously) When the server is told to shutdown
Now, the first one is handled just fine. But the second one is not. In fact, it has caused me a great deal of headache because it keeps throwing exceptions on this line in particular:
Dim _tcpClient As System.Net.Sockets.TcpClient = _tcpListener.EndAcceptTcpClient(IR)
When I hover over while debugging, I can see a few members that reveal exception data I could utilize; but unfortunately those members are private and I don't want to utilize reflection unless I have to since it could slow down performance where there may not be a real reason to.
I have thought of writing in a Boolean check to see if the server received a shutdown signal and that would indicate that it's time to not accept anything, but I want to avoid that if possible.
Is there any way to see if the TcpListener is no longer accepting connections and has had .Stop() called without reverting to catching the ObjectDisposedException that is raised? (because the Socket that is "accepted" is actually a disposed one)
I got 11 errors in my VB program. All the errors look similar: X is ambiguous in the namespace Y
Error line: Imports System.Net.Sockets
Imports System.Text
Module Module1
Sub Main()
Dim serverSocket As New TcpListener(System.Net.IPAddress.Parse("192.168.1.100"), 8888)
Is that possible to create our own server using TcpListener class with IIS being uninstalled?
View 2 RepliesIt seems the most obvious thing, but I just can't work out how to get the length of bytes sent over a network using a TCPClient and TCPListener? This is my code so far:
'Must listen on correct port- must be same as port client wants to connect on.
Const portNumber As Integer = 9999
Dim tcpListener As New TcpListener(IPAddress.Parse("192.168.2.7"), portNumber)
[Code]...
I need to get the length of the networkstream to set the size of the array of bytes I'm going to read the data into. But the networkStream.length is unsupported and does not work and throws an Notsupportedexception.
The only other way I can think of is to send the size of the data before sending the data, but this seems the long way round.
I have a background thread that sits waiting for new clients to connect to my TcpListener and when a new client connects it passes it off onto another worker thread and then loops straight back to waiting for another client. Like so:
[Code]...
Obviously I could just handle the exception and ignore it but I'm sure there must be a more proper way of doing it. One thing I am thinking of trying is using the BeginAcceptTcpClient and EndAcceptTcpClient methods but for one thing I'm not sure if that will actually help and for another thing the Begin and End versions of methods have always confused me in the past... I mean for a start how do you know when to call End?
I figured this must be a fairly common problem but searching the forum only turned up one result and it wasnt any use. I'll keep playing around and trawling google but just wondered if anyone had come across this before?
i made a simple tcp listener server.Now I can use my client to connect,it connets, everything is good. The
problem is when I open the first client, then I open another one, it doesn't connect. It accepts only 1.Any way I can accept multi connections?
[Code]...
OK I am probably going to completely fail but I thought I would just try making an SMTP server (which came from another thread on here I was posting in earlier). At the moment I am just concentrating on RECEIVING emails via SMTP, I dont care about sending them yet.So the first thing I want to do is just make my server program be able to receive a simple HELO command from Telnet on port 25. Simple enough eh? Apparently not The problem I have is that my program starts reading the data as soon as 1 character is typed into telnet, rather than it waiting for the telnet user to press Enter before it starts to process the command. I've had a look around and looked at Athiest's examples but cant figure out how to make it wait. Here is what I have so far:
vb.net
Private Sub StartBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles StartBtn.Click
[code].....
I am trying to learn how to use the tcplistener and tcpclient classes. While I am attempting to compare something that is sent from the client to the server it seems that it adds a bunch of spaces, the reason I know that is if I write to the console what was sent it adds a bunch of spaces at the end. Is there anyway to get rid of it and just get the original text. I tried trim() but that didn't seem to work but I could have been using it improperly.
View 30 RepliesI have a TCPListener demo setup and working. The demo program has been supplied by Bill Chung, here:[URL]..the Listener uses a DataGrid to output whatever data is received but currently it doesnt store it.
Ive created a simple database and linked it to my project. what i need help with is getting the data that is currently outputted in the DataGrid to be stored into my DB table.
[Code]...
I have a tcp server that uses TCPListener and the async method BeginAcceptTCPClient:
Imports System.Net.Sockets
Imports System.Threading
Imports System.Net
Public Class TCPServer
[Code]...
My problem is that infrequently, I get an exception in the HandleAsyncConnection method:"An existing connection was forcibly closed by the remote host" right at the EndAcceptTCPClient method. At this point, the TCPListener seems to stop listening. The problem is that I can't test this easily, as it only happens on a remote test VM and only once every 24 hours or so. If I knew how to recreate the error with a test client, I would be able to figure this out. Wireshark shows a reset [RST] packet being sent at around the time of the exception. So I either need to know how to handle the exception, or how to recreate the problem with a test client.
I got a piece of code that I have to use as a class. It gets added to the project every time, the accessed from the code of the forms.
It is for ethernet communication to an industrial radio.
So right now it's a just a class called MK
Question:
Is it possible to compile a class into a DLL which then can be just referenced to each application?