I'm writing a program which uses sockets, Now the issue I'm having is, If the packet received is over a certain size, the socket then fails to receive anymore packets/data after it.
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What Visual Basic code can be used to assemble and send a raw packet, and receive response packets? I looked on MSDN and I couldn't find any documentation for anything used to send a packet.
View 2 RepliesI am having trouble with a socket client application written in vb.net using Visual Studio 2005. The client connects to a C language socket server that is running on OpenVMS. The problem that I have is that when the server sends a packet, the client does not receive the last byte (of every packet!). I can dump the packets on the network and the data is all there. My current solution is to keep my socket messages short (247 bytes) and send one extra byte past the end of my data.
I would like to include more information in my messages and I cannot find a way to make this work. If I knew 100% how long the packets will be on the network, I could work around this by including an extra byte in just the right places. However, I don't want to make any assumptions about the length of the packets.
Here is a sample of my client receive code:
Private Sub ReceiveMsg()
Dim nTotalBytes As Integer
Dim nNumBytes As Integer
[Code]....
I built a server to receive data from clients.But how can I know the length of every data package.
Dim bteAcceptData(1024) As Byte
Dim myAsyncCallBack As New AsyncCallback(AddressOf ReceiveData)
intByte = EndSocket.EndReceive(pIAsyncResult)
[Code].....
I am trying to communicate to a local AS3 Air app on my PC via sockets. The VB.Net app is acting as a server in this case while the Air app is a client. The .Net app sends data every 25ms to the Air app. I have not send any message termination. I just receive the data on Air app and process it.
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I have been trying to figure out how to use Packet X to Capture Packets from a certain program that uses UDP. Does anyone know how to do so?
View 1 RepliesI need to make a packet sniffer that will give me SSL packets. It doesn't need to give me any other information than the body of the packet, the actual data being sent to me. It does not need to differentiate between different IP addresses. And, it doesn't even need to differentiate between things which are and are not SSL packets. Any packets will be fine, it just needs to support SSL packets. The fewer lines of code the better...
View 5 RepliesI converted some codes from python to VB 2010. My aim is sending query data to multicast IP and get the response. My query data receiving from device which is connected to my LAN. Also the device responding my query and my PC receiving the responce but at this point the VB program freezing.getting response data and printing to console without freezing.
This is the code list;
Imports System.Net
Imports System.Net.Sockets
Imports System.Text
[code]....
Here is the Wire Shark (Network Protocol Anlyzer) screen shots; My computer IP is : 192.168.0.11 and device's IP is : 192.168.0.10.
I am trying to implement SMPP protocol in vb. I am sucessfull in send and receiving packets using sockets. Now I would like to decentralize the functions of my program. I want to implement two programs one for sending and another for receiving using a single socket. I want to receive data through the same socket that was created in another process(i.e., the first program).
View 1 RepliesI've looked through a lot of snippets online and I see a lot of things similar to
Dim bytes(tcpClient.ReceiveBufferSize) As Byte
networkStream.Read(bytes, 0, CInt(tcpClient.ReceiveBufferSize))
but what I am unsure of when to call such a thing? How do I know when there is data to receive...in visual basic 6 with winsock, there was a specific routine which was called upon data arrival, but I see nothing of the sort for vbNet.
I have written a simple Server application that transmits an XML string to all connected clients when the user updates/alters a datagridview. When I connect to this server with telnet I can see the correctly formed xml string.
I have also written a client application, which on reception of the Xml string, displays it in a datagridview. But When I look at the xml string it is either missing parts of in the wrong sequence.
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I am sending data to server via TCP IP Connection. I am using a continuous loop at the server end - that accepts new clients and while streams can be read, it reads data stream.
The data is sent from the client with 2 leading bytes of data that represent the size of the packet of data sent and type of data.
My question is: how do I retrieve the size of the data packet and then check that this amount of data has been retrieved?
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I am sending data to server via TCP IP Connection. I am using a continuous loop at the server end - that accepts new clients and while streams can be read, it reads data stream.
The data is sent from the client with 2 leading bytes of data that represent the size of the packet of data sent and type of data.
My question is: how do I retrieve the size of the data packet and then check that this amount of data has been retrieved?[code]...
I've been using some code which I found on the net, and have noticed that the first byte is never recieved. Annoyingly, this contains the MAC addresses, which is the bit I want. Below is the relevant snippits:
Public Sub [Start]()
If m_Socket Is Nothing Then
Try
[Code].....
I am attempting to post xml to an affiliate and am having some issues. The affiliate will only accept the xml as a string in the name-value pair called "XML" on a classic asp page.
Here is the code file I have, which works fine and gets the response "Invalid XML". I.T. on the other end explained to me that is the message that gets echoed if they get no data on their end from this one statement: XML = Request("xml")
I cant see anything here which would make me think nothing is getting transmitted.
Dim uri As New Uri("http://www.affiliatesite.com?xml=")
Dim packet As XmlDocument = New XmlDocument
packet.Load(Server.MapPath("../XML/TestDoc.xml"))
packet.GetElementsByTagName("id")(0).innerXml = "123"
[Code].....
Since a few months I want to learn how to receive and send packets. Since WinSock doesn't work I think it'll be quite hard to get an easy way to do it.
I want to be able to send and get packets as a client. (TCP) I know that I need System.Net.Sockets, and that's quite everything...
I have created a Client that can send and receive data via TCP sockets. The objects stored on the serverside are the *exact* same object used for the client. They use the same send and receive protocols.
Now, when i send a string from the server to the client , it does precisely what it should do. However when I send a string to the server.... I do receive the string as an equal length of NULL characters. I run the server and client locally.
Basicly what can influence the behaviour between two completely identical objects performing the exact same task? I wonder if there is some socketflag issue if the TCPlistener.accept function returns a completely different setup then the one I R used to.
(if it is of any interest, the send protocol is asynchronious)
I cannot find a way to get the server to put the information of the recieved packet onto a textbox for the user to see.Client Side:
Imports System.Net.Sockets
Imports System.Text
Public Class Client
[code]....
I am also trying to get the server to send back a packet to the client saying it recieved the packet sent. I just dont know how to translate the packet to a textbox.
The following code waits for data over UDP. I have a test function that sends 1000 packets (datagrams?) of 500 bytes each. Each time I run the test function, the receiver gets only the first few dozen packets but drops the rest. I looked at the incoming network data using Wireshark and I see all 1000 packets are actually received, but just don't make it to may app's code.[code]If I add a small delay after each call to Send, more packets make it through; however since Wireshark says that they were all received anyways, it seems that the problem is in my receive code. I should mention that UdpListen is running on a separate thread.Any idea why I am dropping packets? I also tried UdpClient. BeginReceive/ EndReceive but had the same problem. A second issue that bothers me is the global nature of the receive buffer when using Sockets and I am not sure if I don't process incoming packets quickly enough that the buffer will be overwritten.
Based on the various, somewhat conflicting suggestions from replies to this and other posts, I made some changes to my code. Thanks to all who chimed in various bits; I now get all my packets from dial-up to Fast Ethernet. As you can see, it was my code at fault and not the fact that UDP drops packets (in fact I have not seen more than a tiny percentage of packets being dropped or out of order since my fixes). Differences:
1) Replaced BeginReceive()/EndReceive() with BeginReceiveFrom()/EndReceiveFrom(). By itself this had no notible effect though.
2) Chaining BeginReceiveFrom() calls instead of waiting for the async handle to set. Not sure if any benefit here.
3) Explicitly set the Socket.ReceiveBufferSize to 500000 which is enough for 1 second worth of my data at Fast Ethernet speed. Turns out this is a different buffer than the one passed to BeginReceiveFrom(). This had the biggest benefit.
4) I also modified my send routine to wait a couple of ms after having sent a certain number of bytes to throttle based on expected bandwidth. This had a big benefit for my receiving code even though Wireshark said all my data still made it across even without this delay.
I did NOT end up using a separate processing thread because, as I understand it, each call to BeginReceiveFrom will invoke my callback on a new worker thread. This means that I can have more than one callback running at the same time. It also means that once I call BeginReceiveFrom I have time to do my stuff (as long as I don't take too long and exaust the available worker threads).[code]What is not shown above is the error handling and dealing with UDP data being out of order or missing.I think this handles my issue, but if anybody still sees anything wrong with the above (or something I could do better) I would love to hear about it.
i try to transfer packets from the PC to the Mobile phone~ my PC is act as a Server and Mobile as a Client. My Mobile is successfully connect to my PC, but when i try to pass a packets from Mobile, it went failed without any error. The Server didn't receive any packets from Mobile. i had test my code on PC to PC and it's work fine. Anyone have this kind of experience?
View 3 RepliesBelow is my code, but when i send the message thru client socket i receive Specified argument was out of the range of valid values. Parameter name: size
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim serverStream As NetworkStream = clientSocket.GetStream()
Dim outStream As Byte() = _
System.Text.Encoding.ASCII.GetBytes("0800822000000000000004000000000000000920092126012345001")
[CODE]...
I have these following lines to send bytes using socket
Dim server As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
Dim myIp As IPAddress = IPAddress.Parse("myIP")
Dim ip As New IPEndPoint(myIp, Int32.Parse("myPort"))
[Code]....
As in the code, I am supposed to retrieved "Halo". Instead I keep receiving sth like "[]".
I coded a small tcp server/client software implementing the async methods of the socket object. In order to keep track and control of the transfered data on both sides, I decided to wrap the bytes to be transfered into small 65 000 bytes packets, sent one after each other, in varying order.In most cases, it works perfectly, and it is impressively fast. However, when I want to transfer larger data than my usual requests, say like a dozen megabytes, crippling problems start to appear, out of shit.Effectively, it seems that somehow when executed without pauses, the server sends the packets too fast, or that the client receives it too slowly. However, if I put the SendAsync method's thread to sleep for like 100ms before sendingthe next packet, everything arrives without problem on the client.[code]
View 1 RepliesMy client program gets stuck on NetworkStream.Read even though the server is reporting it's sending the message. The client and server are running on the same computer.Full server code (console application)
Imports System.Net.Sockets
Imports System.Text
Module Module1
Sub Main()
[Code]...
I need to include in my application that can receive connections from a client( or two).I am thinking, that I would like to have the clients send a "TelegramID" so that I may now how to process the code.Following the "TelegramID" would be a structure that would need to be processed.So far, I can use a single client and send just plain text but need some direction for my end goals.
View 2 RepliesI realize this is a broad question, but how do I recieve / send packets. I know what packets I need to send and what Im going to recieve, but I dont know how to send / recieve them.
View 8 RepliesWhile using the Socket.Receive method to receive messages through network, you should define a variable as the buffer and you have to specify the length like this: Code: Dim _ReadBuffer As Byte() = New Byte(LENGTH) {} My question is: What is the bad thing about increasing the length of this variable even if the received messages are sometimes shorter? (i.e. if some body let it 10000).
View 1 RepliesI have connected to a host, but how do I find the correct buffer size? (The Buffer is currently set to 8k (8192))
Dim webget As New Net.Sockets.Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
webget.Connect(host, port)
webget.Send(data, 0, data.Length, SocketFlags.None)
Dim rData(8192) As Byte
webget.Receive(rData, rData.Length, 0)
How am I able to send a data packet from my program, to an IP Address on a certain port (using Udp).
View 4 RepliesI am trying to read a packet of data which has come in from RS232. I need to be monitoring the port until data comes in to be actioned. I have been doing this fine for some time using the following code:
Dim strline As String = Nothing
Dim comPort As SerialPort
Dim bIsOpen As Boolean = False
[Code]....
The code above works without a problem unles byte 1 or two are greater than 127. Basically, all of the characters that are not converted seem to be 128-255.
I am using VB 2008 express. Clearly I need to read each byte individually and store it as a byte within an array instead of a string but i am not sure how to do this.
how to get around this either through reading bytes properly or through using a different encoding format
