C#: Client can't connect to external IP server

[RFD]

I've been slaving at this problem for over a week, and would appreciate some help from you kind folks.

Basic Problem: I have made a server program and a client program. When I try to use the client to connect to 127.0.0.1 or my LAN IP, the program connects and transfers information successfully. However, when I get somebody else to host the server, or when I try to connect to a server on my own machine using my WAN IP, I currently get a "Connection could not be made because the target machine actively refused it." exception. I'm not sure what I changed to get this exception I just mentioned instead, but I was previously getting a "Connection could not be made because the target machine did not respond." exception as well.

Here is the jist of the code causing the problem:

Information Initialization Code:

        internal Connection(int port)
        {
            DNSname = Dns.GetHostName();
            IPAddress ip = Dns.GetHostEntry(DNSname).AddressList[0];
            address = new IPEndPoint(ip, port);
        }
 

Server code:

            TcpListener Listener = new TcpListener(IPAddress.Any, address.Port);
            Listener.ExclusiveAddressUse = false;
            Listener.Start(10);
            while (Active)
            {
                if (Listener.Pending())
                {
                    if (RemoteTcps.Count < CommonConstants.MAX_PLAYERS)
                    {
                        Thread ConnectThread = new Thread(delegate() { ConnectToClient(Listener); } );
                        ConnectThread.Start();
                    }
                }
                Thread.Sleep(100);
            }
            Listener.Stop();
 

The listener never receives a request, so Listener.Pendin g() is never true (unless I specify my LAN/loopback address).

Client code:

 
        internal void StartAsClient(IPEndPoint serverIP)
        {
            Active = true;
            Tcp = new TcpClient(this.address);
            remoteaddress = serverIP;
            if (ConnectToServer())
            {
                Thread ClientThread = new Thread(delegate() { LiveClientConnection(); });
                ClientThread.Start();
            }
        }
 
        private bool ConnectToServer()
        {
            try
            {
                Tcp.Connect(remoteaddress);
                return true;
            }
            catch (Exception exception)
            {
                Debug.Error(2, "Connection " + address.Address.ToString() + ":" + address.Port + " to " + remoteaddress.Address + ":" + remoteaddress.Port + " failed.  " + exception.Message, this);
                return false;
            }
        }
 
 

The catch() above in the client code is what is telling me that Connect() failed because the server machine actively refused it.

I have made sure to turn off windows firewall completely for testing, and I have only been using forwarded ports on my router when I host. I have also tried putting the server on somebody else's computer and tried connecting to him through his WAN address, with no prevail, and he doesn't use a firewall, his router is forwarded, and he can successfully host other programs.

I used the MSDOS prompt to ping my WAN address and that was successful.

Someone with a similar problem in another forum was told to use TcpListener Listener = new TcpListener(Dns .GetHostEntry(D ns.GetHostName( )).AddressList[0], address.Port); instead, but that didn't work for me and I think IPAddress.Any is probably what should be used.

Thanks in advance for any help.

[Motoma]

Can you connect to your server, from the client machine, using telnet or netcat?

[radcaesar]

Try after disable ur OS forewall.

[Plater]

I currently get a "Connection could not be made because the target machine actively refused it." exception. I'm not sure what I changed to get this exception I just mentioned instead, but I was previously getting a "Connection could not be made because the target machine did not respond." exception as well.

'target machine actively refuses it' usually occurs when the request reaches the correct port on the machine and there is nothing listening on that port.
'target machine did not respond' is usually related to a firewall blocking the port and stoping a result message from making it back to you (stealth mode).

I would suggest checking up on yours (and others and network's) firewalls first.
Then try a tracert to your wan IP and LAN IP and the LocalHost(127.0 .0.1) IP. Then debug your server with breakpoints at the connection received sections and try to connect to it with like telnet or something.