Is it possible to have a public server application on a network without port forwardn

[ethangk]

Hey
This is a little hard to explain but I will try my best. Is it possible to have a application running on a specific computer on a network, and to have all requests sent from the internet sent to that specific machine, without setting up port forwarding, and if so, is this something which would need to be hard coded into the application, but im inclined to think that it isnt. An example: multiple users on a network can browse the web at the same time, and even without port forwarding set up, the information is sent back to the right machine. I am not sure if this is built into the router though, as web browsing is one of the more common uses of the internet in the home. Another possible example, games which support online multiplayer work, most of the time without having to set up port forwarding.

If you need me to expand, please just ask :)

thanks

ethangk

[Nepomuk]

I'm no expert on network programming, but as I understand it, if the client behind the router sets up the connection (e.g. by requesting some data from the server), the answer should automatically be sent back to this specific client. If however the server tries to connect to the client (and therefore the server becomes a client and vice versa), then port forwarding is needed.

So, if I'm correct with this assumption, that would mean:
ClientSocket => no port forwarding needed
ServerSocket => port forwarding needed

My guess is however, that you can get more specific answers to this in the Networking Forum, so maybe this thread should me moved there.

Greetings,
Nepomuk

[ethangk]

Thanks, will post it in there, unless there is a way to get a mod to move it there?

[kukashna]

Here's what I think is the case, although I'd love to be proven wrong in that there are other possibilities:

Port forwarding will always be required unless one of the following is true:
• Your router doesn't require it.
• You're playing over your own network, and not through the Internet.
• Everyone playing the game is connecting through a dedicated server. None of the players are acting as the server. (In this case, the server would be the one that would need to worry about port forwarding, if applicable, and not anyone playing the game).

I'm guessing every time it seems like port forwarding isn't required, you're really just all connecting to a third-party server (whether or not you're told). That's how instant messengers and such work, anyway.

[kukashna]

Do you need help setting up port forwarding, or setting up a server?

I'm not an expert on servers, but I may be able to help you get started a little, as I've set my own up (on Ubuntu).

You may be able to find a service online that lets people use their servers for such purposes. Here's a random site that might, although you can probably find more suitable ones, since this is the first that came up in my search:
http://www.ultimategameserver.com/