Making my TCP server Internet-facing - where should I start?

I have written a client/server code. The server program executes on a t开发者_运维问答erminal which plainly receives text data from the client and the client is a GUI where in you could specify the IP address of the machine where the server would be running.

However this works only in a closed Network(LAN). I have just learnt TCP IP and have written a few codes that run on a LAN. I wanted to make this program work across the network(over the internet). But I have some basic doubts like,does one need the permission of the local ISP for such programs to execute across the internet.Does it involve buying a domain or some kind of permissions? Can some one please help me on,what should I be doing,or where should I start from?

Listener have to have IP port opened in some way. If you are behind router, you should set proper port forwarding on router and if ISP provides its own subnet, you should know how to setup such link. (i do not know what kind of tehnology ISP might use for this).

For beginning you do not need you own domain name but you should be able to address by ip. If you need domain, register own domain name or create subdomain for free (i was using http://freedns.afraid.org/ )

If your server is behind a router which creates a LAN, you have to configure the router that it will forward the packages from your client to the server. You have to forward all the incoming packages at the specific port to the local ip of the server.