You need to do several things to set up a server application:
- Open up the application's port on the
computer you're running it on. (as a last resort you can simply turn off the firewall, but this is not as safe. If you have a router which you are behind, it shouldn't make much difference though if you trust the other people on the network).
- On the router make sure to forward the application's port to the IP of the computer running the application. This is the local 192.168.210.230 IP that you gave before. This could change everytime you boot up your computer, so you might want to make sure to give the computer in question a static IP.
- Start the application.
- Finally give people the IP for your network which can be done using madcolor's method of going to http://whatismyipaddress.com/. This is your IP to the outside world, whereas the 192 is just IP that is given to you by the router.
To describe when is happening: Your friend types in the IP and his computer makes a request for that IP/port combination which gets sent by the ISP to your router (most applications run on a consistent port everywhere. For example web browsing is always done on port 80, so unless a different port is specified, it is always assumed. You will have to find out what port your application uses). Your router because of port forwarding recognizes the port number on its rules list and then sends the request to your computer's IP. If your computer has no firewall or the firewall is setup to let that port through, then your computer lets the packet be read by the application running on the said port.