TCP服务器IP客户端连接问题

Question

OK so I've just started messing with TCP using c#, and I've successfully set up a server that i can send a 'Hello World' Message to, anyway I've been doing this locally (because both laptops are connected to the same router) i just use the 192.168 number to connect. but The whole purpose of it is to work over the internet, and the routers ip address is obviously the same for both computers, if i type the routers IP address it doesn't work, and if i type the 192.168 number that definitely won't work over the internet... So what IP do i use, or what is a better solution?

here's the line of code if it matters

 var client = ScsClientFactory.CreateClient(new ScsTcpEndPoint("192.168.1.142", 10085));

Where 192.168.1.142 is the local ip of the laptop with the server started on it

and 10085 is the port.

Answer 1

You have to configure your router to forward any incoming connection to the port 10085 to you local IP adress. Then anyone will be able to connect using your external IP adress.

Each router has it's own configuration system so you have to search "port forwading" and your router model in google.

Answer 2

It depends on what your trying to acheive i guess. If for example your making a chat application. The client (behind the router) lets say its local IP is 192.168.1.111 and router IP is 80.120.78.100. The client would connect to the server.

Once that connection is made it doesn't matter about sending back to the client because the connection is already open between client and server so the server would just use the same connection. The router figures out where to "route" the packet, stuff which generally you dont need to know about.

If however your server is the one looking for clients, then thats different.

Answer 3

I'll try to explain a little about networks, but you'll have to search about it .

Basically , understand an IP mask , such as 192.168.1.0 as one network. Router's role is to connect different networks, that's why a router typically has 2 ports, WAN (wide) and LAN (local).

With this concept, you can see the internet as one big network made from the connection of various ISPs. Each ISP has a router to its network, and another one that gives you an internet connection. Finally, you have a router at your home. So, from this, you can understand that there are 3 networks connected: your home, your ISP and the internet.

In order for you to be able to connect to a computer at my home, I have to make this computer available from the internet, I have to publish it. I do this by setting up a NAT (network area translation) at my router. This NAT says "anything that comes from the internet on port 12345, forward to 192.168.1.10 (my server) at port 80".

This is an extremely simple explanation, ok?

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Now, let's take a big step back. If you have another computer available on your network, you can test if your program is working with a much simpler approach.

1. Connect both computers to you LAN , so they will acquire similar IP addresses. Let's pretend they are 192.168.1.10 and 192.168.1.20
2. Run the server at 10 and disable all kind of firewalls (Windows and third party)
3. Run the client at 20 and try to connect to the server