I'm creating a server client application. I have been able to connect to applications on the same network. For example I can connect to 10.0.0.3 and 10.0.0.4.
Now I have been trying to connect to my external IP and I recieve:
System.Net.Sockets.SocketException (0x80004005). No connection could be made because the target machine actively refused it.
listen = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
write = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
end = new IPEndPoint(IPAddress.Parse(IP), 3212);
write.Connect(end);
Is this a problem with my code or with my router settings? Or is it that you can't connect to yourself... however that wouldn't make sense considering I can connect to 127.0.0.1.
This is a common loopback error, because you're router gets confused when doing Internet NAT redirections. Your external IP is assigned to your modem/router...not your computer, remember that your router could be handling traffic for more than one device inside the network under one single external IP then it uses NAT to redirect traffic to specific local connected devices. One example is, your home network with 2 computers, one printer and 2 mobile devices, all of them connected to your home network via wi-fi, all of them will have a local IP address assigned possible via DHCP, however, the external IP address is the same for all local devices because the external IP address is assigned to your router.
When connecting to local network devices ALWAYS use a local IP address instead of the external one
Edit
I wanted to keep this answer as simple as possible but Scott's comment made me re-think that it is always useful to add details that can help the community out there.
Basically, you can actually set up Port Forwarding which allows your router to redirect incoming traffic received in a specific port to a designated device in your local network. This will make your device accessible from outside your network on that specific port and you can easily take advantage of this to connect to sockets from inside your local network using your external IP address. The flip side is that not all routers/modems support Port Forwarding, so you will have to refer to your modem's manual and check if it's supported or not.
But, if you want to set it up solely for the reason that you want to connect devices from your local network using the external IP, I would recommend you NOT to do it and use the internal IP address, you don't really want to go through the security risks that are involved in exposing your local devices to the internet. You can easily set up strict firewall rules to outsiders and a more relaxed security in your local network.
For my socket application I used port number from 10000, secondly I have created Windows Firewall Rule on socket server computer, which allows your external client to connect to the socket server. you can specify number of individual ip address or a range with a port number 10000. From Start -> All Programs -> Windows Firewall with Advance Security. Follow the prompts set the rule for your client IP. Good luck
I presume the IP address you want to connect to is not 127.0.0.1, but your own IP address as used on the internet (e.g. 80.110.140.30)? You can't do that. Try copy-and-pasting that same IP address in your browser, for example, and you'll see it either does not connect or redirects to your router.
From your own network, the only way to connect to yourself is through the loopback device (localhost or 127.0.0.1).
Related
I'm working on a simple c# messenger and its works on the local network only. Does somebody know what should i do to make it works on the internet?
The solution contains the server project that listening on a certain port, and a client project connect to the server with that port.
Your clients need to be able to communicate with the server, which means that either:
You need to host the server application on a computer that is directly connected to the internet.
You need to setup port forwarding on the router that controls internet access for your network.
In either case the clients will need to know the IP address to connect to, and any firewall interactions need to be considered. This may also include ISP firewalls, as some ISPs limit inbound connections to subscriber connections.
I won't go into the specifics of setting up port forwarding on a router... there are plenty of examples, and every router is different. Google will help you with this if necessary.
Ideally you should have a static IP address for this, or some method for the clients to locate the IP address that your server is hosted on. If you must run from a dynamic IP address (such as some ISPs still use for subscribers) then one of the Dynamic DNS options might work for you.
In-order to make it work on Internet a simple answer is you need to enable ports which is used for communication.Generally the ports will be blocked by the Companies firewall for security reasons.So contact your IT dept to enable the port.
Or Use common port like 80.
I am trying to make a winforms client/server chat application. I already have a client and a server, both are working fine, i can log in, send messages, etc .. The problem is that it only works if i connect to my local IP. When i try to run the program with my external IP, i get the following error:
"The requested address is not valid in its context".
In other words, i can run the server on my own computer, start up (for example) 3 clients and let them connect to the running server. This basically means that i'm talking to myself. What im trying to do is to run the chat server on my computer, and let other people run the client-program and connect to the server through the internet.
this is the part where i get an error when i enter my external IP:
public void StartListening()
{
// Get the IP of the first network device, however this can prove unreliable on certain configurations
IPAddress ipaLocal = ipAddress;
// Create the TCP listener object using the IP of the server and the specified port
tlsClient = new TcpListener(ipaLocal, 50702);
// Start the TCP listener and listen for connections
tlsClient.Start(); <--- THINGS GO SOUTH HERE
// The while loop will check for true in this before checking for connections
ServRunning = true;
// Start the new tread that hosts the listener
thrListener = new Thread(KeepListening);
thrListener.Start();
}
im not sure if what i'm trying to do is possible? i can't imagine it is, but i kinda dont know how to proceed with this. I'm new to network programming so any help will be appreciated.
kind regards,
Jane
Jane,
I think your issue is with your IP address setup. This is a network connection problem. You need external IP address so that outside clients can contact your PC. You need more advanced networking. The IP address provided from you ISP is used for domestic uses. You need specialized public IP address so that clients can find you outside of the firewall. This is networking/ISP/external IP issue.
Your server application needs to listen to incoming connections on a specified port, on a specified locally installed NIC. That is why TcpListener always needs to be created using a local IP address: because it only cares which NIC (if you have multiple installed) it should use.
The MSDN page for TcpListener also states it explicitly:
TcpListener Constructor (IPAddress, Int32) Initializes a new instance of the TcpListener class that listens for incoming connection attempts on the specified local IP address and port number.
External IP address is completely irrelevant to a TCP/IP server. You can have numerous routers and network devices along the way, which can then forward incoming connections to your machine.
Just do make sure that your firewall and router are configured properly to allow incoming connections on a specified port. To do that, start your TCP/IP server to open the port, and then use a service like CanYouSeeMe to see if server can be reached from outside.
Regarding your comment (this can prove unreliable on certain configurations), it's obviously "unreliable" when you think about it: a laptop can easily have an Ethernet network controller with a completely different IP address than a Wifi network adapter. Your server app should allow the user to select which IP address to use, instead of picking the first address it gets.
I've spent the last month writing a multiplayer game. I have only been testing it on one machine, using 127.0.01:9051 as the IPEndPoint.
I changed the IP address to my WAN IP, configured port forwarding on my router, configured my software firewall etc... But, it doesn't connect.
I have checked if the port is open using this site. Result: the port is really open.
Also, when I check the port from that website, my server receives packets just fine; however, when I connect from my own machine... it doesn't receive anything.
I've broken everything down to the basics to make sure it wasn't a problem with my code.
This basic code does not work:
IPEndPoint iep = new IPEndPoint(IPAddress.Parse("XXX.XXX.XXX.XXX"), 9051);
TcpClient client = new TcpClient();
client.Connect(iep);
Any ideas are much appreciated.
If you are attempting to connect to the IP that is Forwarded (outsideIP) to the same machine (insideIP), it won't work. There are very few enterprise firewalls and no consumer devices (I know of) that will route a packet from the inside out and translate it back in.
[Internet] -- outsideIP[Router/Firewall]insideIP1 -- insideIP2[Computer]
In this case, packets from insideIP(X) will not be able to connect to outsideIP.
Try to see if you can telnet to your wan IP on port 9051. Routers don't really like it when you connect to their wan IP from within the network itself.
You could use Dyndns or some other service for the outside world to connect to your server and put the same name into your host file that resolves to 127.0.0.1 so that you can connect internally.
Is your client and your server (both the same machine in your failing test) using the same endpoint ip/port? You can only bind a port once at a time. Try using two ports one for server in one for server out (clinet in). That way they will not clash. Use Telnet to check you can connect to the IP/Ports you are using and Netstat to check they are not in use already.
I am creating an application that listens for connections (server) from a different application (client) via a tcp connection. So if both application where to be on the same network it will be easy to establish the connection. so I am trying to add a method to the server so that users do not have to open ports on their routers in order to make the app work when using it over the internet. so let me show you a few different scenarios:
1)---------------------------------------------------SCENARIO_1-------------------------------------------------------------
the server is a computer in a house. That computer is connected to a router and that router is connected to the internet. The client is a computer on a office that has access to the internet as well.
for this scenario to work, before I used to open the ports on the house router and forward them to the server computer. on the client I just had to supply the correct IP address and same port in order to establish the connection.
now I avoided opening the ports on the house router with a really cool technique:
first I add this reference:
then I tell the router which ports I want to be forwarded to my computer (the server):
NATUPNPLib.UPnPNATClass upnpnat;
NATUPNPLib.IStaticPortMappingCollection mappings;
public ServerExample()
{
InitializeComponent();
// server local IP address
mappings.Add(1300, "TCP", 1300, "192.168.0.120", true, "my server");
//.... etc
..
when doing this I am able to connect from my office computer by providing port 1300, the WAN ip address of the server computer which is a different one. (that address can be found at: whatismyipaddress.com) THE COOL THING IS THAT I DO NOT HAVE TO DO ANY CONFIGURATION ON THE ROUTER!!!
2)-----------------------------------------------SCENARIO_2----------------------------------------------
know here comes my problem. The server happens to be on a office. that server is connected to router A, router A is connected to router B and router B is connected to the internet. In other this example is like the last example on the server with an extra router in between. and the client is somewhere else. we do not care how the network setup is on the client computer as long as it has internet access.
the way I used to solve this was by forwarding the packages from router x to the server computer and also port forwarding the traffic from port x of router B to the ip address of router A. when setting up that configuration I was able to establish a connection with the client when providing the WAN ip address of the server. (the ip address that is shown at: whatismyipaddress.com when retrieved from the network of the office).
so it will be nice if I can avoid doing all this configuration on the routers and do something similar to:
public delegate void SomeDelegate(string parameters);
NATUPNPLib.UPnPNATClass upnpnat;
NATUPNPLib.IStaticPortMappingCollection mappings;
public ServerExample()
{
InitializeComponent();
// server local IP address
mappings.Add(1300, "TCP", 1300, "192.168.150.141", true, "my server");
mappings.Add(1300, "TCP", 1300, "another ip", true, "router's ip");
so I have been playing around with that and I have not been able to make it work. also it will be nice if I could find out if the server connection is like scenario 1 with c# or scenario 2 or maybe a different scenario so that the users setting up the server do not have to specify all that info. for example I am sure that limewire does something similar.
Edit:
here is scenario 1 illustrated:
and here is scenario 2 illustrated
The feature that you are using is called Universal Plug and Play (UPnP) which is basically a way for a device to tell another device how to communicate with it. What you are doing is telling a computer to tell the router what ports you want forwarded to it. Unfortunately UPnP is a non-routable protocol which means that it can't jump across routers. So the short answer is that doing what you are trying will not work with multiple routers without manually configuring the ones "farthest" away from the client.
It might be possible to do something with Internet Gateway Device protocol (IDG) but you'd have to research that more and the library you are targeting doesn't support that. Post this question to Server Fault and you might get a better answer. (Don't post your code, just explain the basics of your problem, that you're trying to have a machine register itself with a router using UPnP which is working but you have another router in front of that that you want to automatically forward, too.)
I have a web server with multiple IP addresses that needs to connect to a database server. The DB server is behind a firewall that's controlled by an IP address whitelist. (If it matters, it's an Oracle server.) Is there a way to specify the IP address used by the web server in the OracleConnection, so that only one IP needs to be added to the whitelist?
I see there are a few similar questions about specifying outgoing IP addresses (such as this one and a couple linked from there), but none that specifically mention database connections.
The database side doesn't come into play (much).
On my simple network, I have a modem/router that gets an internet IP address from my ISP and has a different IP address for the local network. I have configured it to forward requests made on port 80 (the port used for HTTP requests) to a particular IP address on my local network.
IP addresses can by allocated dynamically (DHCP) or statically. Because I want my HTTP requests to go to a particular machine, I need that machine to always have the same IP address. One way to do that is have the machine request a static IP address when it connects to the network. Another is to have the router dynamically allocate an IP address but to always use a specific one for a specific MAC address. I've gone the latter route. Which you choose to do and how you do it depend on your situation (eg OS and network setup).
In your situation you want the local network addresses to be static for both the database server and the web server. That's really a networking issue.
The only time that programming may come into play is if you have multiple network ports. Take my laptop. It has a WiFi card and an Ethernet port. Each of those has a unique MAC address (actually every network device in the world has a unique MAC address). I can connect either or both of those ports to a single network or to two different networks.
If I connect both devices to the same network, they must have different IP addresses because an IP address needs to be unique to a network so the network knows where to send the messages. If I connect them to two different networks, then they might get the same IP address. [The Internet is one big network, but local area networks (LANs) are independent.]
If your machine has multiple network connections, you may need to direct a particular connection to a certain network (so I might always want my db connections to use the eth0 port and other things to use and eth1 port).
Generally speaking for a web server, you have one or more externally addressable IPs, but only one internal one.
The internal address is what is connected to your internal network for communicating with things like database servers. The external ones are used when outside clients connect or for outbound communications..
I would assume that the "multiple IP addresses" are in the DMZ (external network) , and that the database server is in a different (internal) network, no? You should not have this problem.