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'No connection could be made because the target machine actively refused it'

I am working on a 'Smart Device Project' using .Net Framework 3.5. I am trying to connect to some Java SOAP services on a remote server.
In order to do that, I added 'Web References' to my project.
When I try to call my web service I get a WebException 'Unable to connect to the remote server' with the inner exception being 'No connection could be made because the target machine actively refused it'.
I searched quite a lot on the Web and StackOverflow and found a lot of ASP configuration and 'Unavaliable port' answers, but as I have another application using the exact same Service successfully, I can't get why the new one isn't getting through (It did sometimes through my tests so I suppose my client implementation isn't that bad)
I tried to look if there was some connection issue on the port by using some TcpClient:
System.Net.Sockets.TcpClient client = new System.Net.Sockets.TcpClient();
try
{
client.Connect("myServerName", 8087);
MessageBox.Show("Success");
} catch (Exception ex)
{
MessageBox.Show("Failure");
}
finally
{
client.Close();
}
This connection succeed.
Here is a sample on how I call my WebService:
WSServiceExtended srv = new WSServiceExtended();
srv.Proxy = new System.Net.WebProxy();
ServeurWSI wsi = new ServeurWSI();
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
wsr = srv.login(wsi);
The service is called 'Extended' because I overrided the auto-generated one in order to add Cookie managment since I am using the Compact Framework. Following the sample in this thread:
https://social.msdn.microsoft.com/Forums/en-US/34d88228-0b68-4fda-a8cd-58efe6b47958/no-cookies-sessionstate-in-compact-framework?forum=vssmartdevicesvbcs
EDIT:
I made some new tests with the Web references and got it to work.
When I add the Web Reference, I have to put some Url to the Web Service. When I set it with the actual hostname instead of the 'localhost' everything is fine.
But then, since I set it manually to the real address just before the call, it shouldn't matter
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
EDIT2:
I might have forgotten some specifics about my environnement.
The Web Services are exposed on my computer on some Tomcat Server.
The application I am working on is also developped on this computer (That's why I can add Web References by putting 'localhost' in the address)
The application is then deployed on a distant device (Windows CE) that will make calls the Web Services through WIFI (There, localhost wouldn't work then)
I tried calling the Web services from other computers successfully.
I'm beginning to think that there might be some differential between the called Url and the one that is set, otherwise, how would I have a difference in behaviour such as the one described in the first edit?
EDIT3:
Well..Seems like it's not a network issue but a .Net compact framework (usage?) issue...
The Url property of the Web Service implementation is simply ignored and the one in the Reference.cs is used in place.
If someone had some idea on how I could troubleshot this, I would really appreciate it.

That error means that you reached a server and the server said "no way". So you're either hitting the wrong server or the wrong port.
I find the telnet client is useful for testing stuff like this. From the command line, you can do:
telnet [servername] [port]
So something like:
telnet myServerName 8087
If it goes to a blank screen, then it connected successfully. If it does not connect, it'll tell you.
The telnet client is no longer installed by default in Windows 7+, so you'll have to install it. See here for instructions: https://technet.microsoft.com/en-ca/library/cc771275
If the connection does open, you could paste in an actual HTTP request to see what happens. A simple GET would look something like this:
GET /myServerApp/services/myService HTTP/1.1
Host: myServerName:8087

One reason for this error can be that the service binds to only a certain IP address. It could well be that the service only listens on the IP that is assigned to the host name, but not on the localhost IP (127.0.0.1).
For example:
If the host myServerName has the public IP 192.168.0.1, your service can choose to listen on all IPs assigned to the host (sometimes specifying 0.0.0.0), or it can specifically listen on 192.168.0.1 only. In that case you will not be able to connect through 127.0.0.1, because the service simply doesn't listen on that IP.
You can "use" this inverse of this feature to make a service accessible only to local clients, not on the public IP-Address, by listening on 127.0.0.1 only, but not on the public IP. This is sometimes used on Linux for example to make MySQL only accessible on the host itself.

I was starting to forget this post but I finally found the problem that was messing things up and it has nothing to do with programmation.
I was doing the calls while the device was connected to the computer via the 'Windows Mobile Device Center' allowing to access the device from Windows.
While connected, the host provided is ignored and all calls on the specified port are handled by the connected computer.
Disconnecting the device allows to communicate properly...

Unable to resolve hostname over vpn

I've been trying get my app to connect to a WCF service within the corporate network.
We use a VPN to keep everything somewhat hidden and secure.
I've tried several different methods and I'm unable to get the phone to connect to the service.
I first added the service as a service reference, and built the client out with the correct URL, but this just did nothing and then failed with a nondescript error message after around 50sec.
I then switched to System.Net.HttpClient. This again failed after around 50sec, but this time it threw a System.Net.WebException with the message "A server with the specified hostname could not be found".
I finally tried the ModernHttpClient as well, and this had the same result as before.
(Note that I tried the first two in a test console app project on my local machine first to make sure that they would complete a request successfully)
To make sure I wasn't going crazy and that the VPN was correctly resolving the name, I created a test page within the app which solely has a WebView on it, with the source set to the service url.
I opened the app and navigated to the test page and it loaded the service definition page without a problem.
for reference, this is the current code I have using ModernHttpClient:
using (var client = new HttpClient(new NativeMessageHandler()))
{
const string soap = "<soap msg>";
client.DefaultRequestHeaders.Add("SOAPAction", "<service namespace>");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("text/xml"));
using (var response = await client.PostAsync("http://<url>/Service.svc", new StringContent(soap, Encoding.UTF8, "text/xml")))
{
using (var content = response.Content)
{
// parse the xml result
}
}
}
Is there something special that I should be doing to tell the HttpClient that it has to use the VPN? I thought that this was handled automatically.

I looked into the VPN configuration to make sure it was correct.
I looked into the DNS configuration to make sure it resolves correctly.
I looked into the phone's configuration to make sure it was correct.
I eventually found the issue is a problem with Airwatch's Tunnel VPN.
The VPN only works the first time the app is launched.
If the VPN remains open and is not closed before the app is restarted, then it will not allow connections to pass through.
Expecting a patch form airwatch soon that should (hopefully) rectify the issue!

Silverlight client consuming WCF service

Please bear with me as I am new to WCF services/ Windows services. I've created a WCF service hosted in a Windows service. I want to consume that WCF service in a Silverlight in-browser application over TCP. Below is the code fragment in Silverlight to access WCF service:
var messageEncoding = new BinaryMessageEncodingBindingElement();
var tcpTransport = new TcpTransportBindingElement();
var binding = new CustomBinding(messageEncoding, tcpTransport);
// Create a channel factory for the service endpoint configured with the custom binding.
var cf = new ChannelFactory<ICalcService>(binding, new EndpointAddress("net.tcp://192.168.2.104:4508"));
// Open the channel.
ICalcService channel = cf.CreateChannel();
// Invoke the method asynchronously.
channel.BeginAdd(9, 5, AddCallback, channel);
private void AddCallback(IAsyncResult asyncResult)
{
try
{
double endAdd = ((ICalcService) asyncResult.AsyncState).EndAdd(asyncResult);
}
catch (Exception exception)
{
throw exception;
}
}
The code works fine sometimes but often it throws an infamous System.ServiceModel.CommunicationException with the following message for some reasons:
Could not connect to net.tcp://192.168.2.104:4508/. The connection attempt lasted for a time span of 00:00:00.1010058. TCP error code 10013: An attempt was made to access a socket in a way forbidden by its access permissions.. This could be due to attempting to access a service in a cross-domain way while the service is not configured for cross-domain access. You may need to contact the owner of the service to expose a sockets cross-domain policy over HTTP and host the service in the allowed sockets port range 4502-4534.
The innerException of type System.Net.Sockets.SocketException says
An attempt was made to access a socket in a way forbidden by its access permissions.
What are the possible reasons behind this exceptions? Based on what I investigated so far, I could find only one reason: Improper ClientAccessPolicy.xml. What may be the other reasons? If you have any useful resources, please provide me the same. One more question, if I want to make Windows service hosted WCF service to get consumed by other machines on LAN, what settings do I have to make? E.g. firewall settings? My code cannot access WCF service on other machine. It throws the same exception I mentioned above. Any ideas about how to get rid of this exception?

Problem sorted..!! I had to do following things:
1) Specified SecurityMode.None while creating NetTcpBinding in Windows service.
2) Created an Inbound Rule in Windows Firewall With Advanced Security to allow TCP traffic on the port I specified in the end point address.

Avoiding the timeout exception while connecting to a https url to send request to a web-service

In a dotNet mvc application, while trying to send requests to a http url, my application is working as expected. However, when I try to send requests to a https url, I get the following error ( upon publishing the app in IIS and running it in a web browser) :
Server Error in '/dotnetstage' Application.
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 10.63.64.146:443
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 10.63.64.146:
I understand that it has got something to do with the SSL certificates, so I found that there's a way to ignore certificate validation:
WebRequest webRequest = WebRequest.Create(reqURL);
ServicePointManager.ServerCertificateValidationCallback += delegate { return true; }; //this line works for the certificate validation ignoring
Even then, I am getting the same error. I have two queries:
Am I adding the ServicePointManager line at the proper place? If not
what is the correct location where you add this in your code?
Is there anything else I need to take care of ?
Any help or at least a pointer towards the right approach will be higly appreciated. Stack Overflow helped me a lot with learning to code in c# mvc apps and build complex caller applications in a matter of 4 weeks and I look forward to getting a quick solution to this as well. Thanks. :)

The ServerCertificateValidationCallback should be defined first before making the web request. But in your case the issue is totally different it could be that the web server side code crashed before it could send a response back.

Using C# WebClient with a Proxy - no request made to proxy server?

We have a background operation (Window service) that we want to use through a proxy server.
Basically, we're doing this:
public WebClient GetWebClient(){
var webClient = new WebClient();
webClient.proxy = new WebProxy(Configuration.ProxyHost, Configuration.ProxyPort);
// add a bunch of headers to the WebClient (sessionids, etc.)
return webClient;
}
The proxy is one that we have configured ourselves using FreeProxy.
I've enabled logging and on the machine I'm testing with, and can confirm that requests are being made to the proxy when using it in Firefox.
No authentication is required for the proxy server, except that the IP has to be within our office (which from the Firefox evidence, I assume is not the problem).
However, within our background process, I don't seem to be using the proxy when I use the webclient:
using(var wc = GetWebClient())
using(var s = wc.OpenRead("someurl"))
using(var sr = new StreamReader(s)){
return sr.ReadToEnd();
}
I receive no errors from the proxy however, it seems like we're just going along without it even though the proxy has explicitly been set.
The information seems to return fine, just not through our proxy.
Is there something I'm missing when using a proxy with a WebClient?
edit: more details. If we disable the proxy service on the server, then we get an exception that we can't connect. So it seems like the webclient is attempting to reach out to the proxy, but that traffic is not actually flowing through the proxy.
Inner Exception: SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

It turns out that FreeProxy wasn't accepting HTTPS traffic.
I guess the proxy must return the types of traffic it can route, and if it cannot, the webclient does nothing.
Switched to using the Burp suite as our proxy since it can accept HTTPS.
http://portswigger.net/burp/

You either have to configure windows for using the proxy by default, or set the proxy manually in your code, see: http://msdn.microsoft.com/en-us/library/system.net.webclient.proxy(v=VS.100).aspx

You are using the WebClient class correctly as far as I can tell. I am able to see the following request...
using(var client = new WebClient())
{
client.Proxy = new WebProxy("localhost", 8888);
Console.WriteLine(client.DownloadString("http://www.google.com"));
}
in Fiddler running on my local box. Now if I shut Fiddler down, I get the WebException:
Unable to connect to the remote server
With an inner SocketException of:
No connection could be made because the target machine actively refused it 127.0.0.1:8888
So, with that said, my guess is that your proxy is working as intened but it is just not logging the outgoing HTTP request.