.net - How To Handle TCPListener "An Existing Connection Was Forcibly Closed By The Remote Host"
Aug 5, 2011
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 have a fat VB.NET Winform client that is using the an old asmx style web service. Very often, when I perform query that takes a while or pass a large amt of data to a web service in a dataset, I get the subject error.The error seems to occur in < 1 min, which is far less than the web service timeout value that I have set or the timeout value on the ADO Command object that is performing the query within the web server.It seems to occur whenever I am performing a large query that expects to return a lot of rows or when I am sending up a large amount of data to the web service. For example, it just occurred when I was passing a large dataset to the web server:System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the rem
I have an application that copies a file from a network/internet location. I am trying to catch the exception for when the network connection becomes unavailable (or internet goes down). Currently i catch the exception "Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host." which occurs on the bold, underline line below.The issue i have is i try and attempt the operation to continue doing what it was doing by resetting variables and then reassigning them to continue reading the stream but cant get past this error. The only way to go past it is to stop and start the application which is not what im after. [code]
Below error is thrown in a already opened program which connects to different database
A transport-level error has occurred when sending the request to the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)
Program details: code done using vb.net with MSSQL 2008 as back-end
Two instance of same exe where running simultaneously in same PC but error was thrown only by one instance Program uses both sqlconnection(ADO.NET) and ADODB connection(upgraded from VB6) and the error is thrown by both types of connection. If the error is due to network problem with the server then why few programs work fine? I am not able to trace the reason for this behavior of the program. Can I know why this error occurs and why only in few programs of same instance.
Rather than use an Entry name of an existing VPN connection, is it possible to connect to a remote network by creating a temporary connection on the fly by using the remote IP/Host name, username and password?
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....
I have a simple scraper. It works on some websites, but on some there is this Error:
Quote:
IOException was unhandled Unable to read data from the transport connection: The connection was closed
It is occuring at "Dim htmlresults As String = Urlcontents.ReadToEnd()".
'Create the HttpWebRequest object Dim req As HttpWebRequest = WebRequest.Create(URL) 'Set the timeout to 1 second (or 1,000 milliseconds) req.Timeout = 10000
I've been trying for a long time to do what seems to be the most simplest of things..I have a remote host and I need to know if certain posts on that host are open or closed.Many examples on the net that I have found arent complete, and because I havent worked with VB.net for long I dont knowhow to complete them.Here is my code:: The issue is with this it tell me the target port is always closed, when I know that it is open.Code:Dim host As String = "www.google.com" Dim port As Integer = 80 Dim addr As IPAddress =CType(Dns.GetHostAddresses(host)(0), IPAddress) Try Dim tcpList As New TcpListener(addr, port)tcpList.Start() Catch sx As SocketException MessageBox.Show("port is closed") End TryA friend of mine suggested using WinSock.. I've not dealt with it before so I don't know what he's on about.
Does someone know what api funtion to use for getting remote host name right now i use System.Net.Dns.GetHostName and the nbtstat -a function, but still have some computers that i dont get their host name but i do get their mac with send arp...so how cna i get their host names with an API call..
This is my code for dns.hostname ..
vb.net Dim myIPs3 As System.Net.IPHostEntry = Dns.GetHostEntry(hello) Dim newhost3 As String = myIPs3.HostName
I'm developing a device app in VB.net that will access a SQL Server database. I need to establish a connection when the app is launched, and keep the connection open until the app is closed. I've done the following:In the Master Module:
Public CNN As SqlConnection
In the Main menu form load:
CNN = New SqlConnection(sqlConnString) CNN.Open()
Then when I want to read from the database:
Dim sqlDR As SqlDataReader SQL = "SELECT Name FROM Table"
[code]....
When I run the same code without the global CNN, but rather dim the connection inside the Select function, all works well.
I'm trying to insert a new records into database, one of those records is a "datetime"...when I type a wrong date, and try to insert those values into database, i get an error (about wrong typed date etc.)...ok, that's fine, things need to work that way. But here comes the problem, I correct the date, and then try to insert values again...here I get an error from the post title. And this doesn't work until I close that form and run it again...here's part of my code:
Dim cvLicence As New SQL Try cvLicence.upis("INSERT INTO blabla (itsnotimportant) VALUES ('something')") MsgBox("everything's fine", MsgBoxStyle.Information)
When I to connect to remote host to retrieve sql record...
it execute to few minute will get his error message... but there is already work perfectly and get connected... it loop it a few record only will occur this error...
"Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host."
I have created a Windows service that runs on one of our servers. The service lisens to incoming connections on a set socket port, runs a series of WMI queries on the requested computer in a new thread (the socket accepts a string value as input which is the hostname to scan), creates an xml file based on the collected data, and posts it back to a webserver. This works perfectly on all WMI queries, but i have one function that gets all installed software from the requested host using the RegistryKey.OpenRemoteBaseKey method to get all keys from the "SOFTWAREMicrosoftWindowsCurrentVersionUninstall" key on the target host. If the the target machine OS is Window Vista or 7, it returns no values. If i run this code on the target machine it works, but not from the service on a server. The service is installed and runs with full domain administrator rights. I guess this is a permission issue, but i have not found a good solution on how to solve it on the internet. As a workaround i use WMI to get a list of installed software from computers running Vista or 7. The problem with the WMI method is that it's very slow. It takes 10 - 15 seconds just to loop thru all ManagementObjects in the Querycollection. Maybe i could filter the WMI query better before starting the loop ?
way to retrieve list/rename hiddne files from the remote host. I need to upload the file to a server and then move it to another directory, but the file after being transfered becomes hidden. If I try to rename it any way I get the dreaded 550 in response. I would hate to move to commad line scripting which at the moment seams to be my only option.
I'm making a winforms app in vb.net that connects to a mysql database on my webserver to read and write data, this all works fine.But i have to allow the users ip to remote connect to the database.Is it possible to give everyone access to the database? The user account will not have all rights an the data isn't very important if it got lost.The user account and connection details are hard coded.
I am using the visual studio 2008 but use the guide for 2oo5 .I wonder why the program show error after click the load button (btnload). I am following the http: [URL] and having problem with the 'Filling the DataSet'. Is it because of different version?
The code I use: Public Class Form1 Private Sub Ordered_booksBindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Ordered_booksBindingNavigatorSaveItem.Click Me.Validate() Me.Ordered_booksBindingSource.EndEdit() [Code] .....
I have a problem connecting to an access database. I'm currently trying to build a login/register program that reads the username and password from a database and allows login if the specified username and password are found. I have code that will work properly for that so that's not an issue. However, when I make an attempt to register a new username along with a bunch of other things such as email, password, etc. I am unable to because the database connection is closed. The code I'm currently using to open the database connection is :
[code]...
However, when I try to use this code to open the connection to the database, it leaves the connectionstate closed. I decided to then build in as a test, a block of code that would check on load to see if the connectionstate is open or closed. Each time I've run it so far by making a few changes it always tells me that the connectionstate is closed no matter what I do.
I have create a simple app in vb.net that receive data from a bluetooth device ( data are simple strings like "90123.9mm"). Is there a way to check if the device has closed the connection ?
Im having 2 errors when loading the form the first one is: "The connection was not closed. The connection's current state is open" and the another one says "Conversion from string "" to type 'integer' is not valid" and everytime I change cmb_Suc appears: "The connection was not closed. The connection's current state is open" [Code]
I have a form that contains a crystal report viewer. When I open this form, it runs a report. I am using a .LDB viewer to tell who is logged into an access database. I noticed that when this form opens, the computer logs into the database and stays logged in. Even when the form is closed, the computer is listed as "logged in". If I run the report again, it just adds another instance of that same computer logged in. Therefore, it continues to pile up logins until the application is closed.
