I am trying to create a multiplayer game for iPhone(cocos2d), which is almost finished, but the multiplayer part is left. I have searched the web for two days now, and can´t find any thing that answers my question.
I have created a search room(tcp socket on port 2000) that matches players that searches for a quick match to play. After two players has been matched, that server disconnects them from the search room to leave space for incoming searchers(clients/players)
Now I´m wondering how to create the play room(where two players interact and play)?
I was thinking I could create a new tcp/udp socket on a new port and let the matched(matched in the search room) players connect to that socket and then have a perfect isolated room for the two to interact with each another.
Or do I need a new server (machine/hardware) and than create a new socket on that one and let the peered players connect to it.
Or maybe there is another way of doing this.
OBS. I am not going to have the game running on the server to deal with cheaters for now. Because this will be to much load for the server cpu on my setup.
I was thinking I could create a new tcp/udp socket on a new port and let the matched(matched in the search room) players connect to that socket and then have a perfect isolated room for the two to interact with each another.

Yes, you can do that. And there shouldn't be anything hard about it at all. You just bind a socket on the first available port, pass that port to the two players, and wait for them to connect. If you're worried about hackers swooping in by, e.g., portscanning for new ports opening up, there are ways to deal with that, but given that you're not attempting any cheap protection I doubt it's an issue.

Or do I need a new server (machine/hardware) and than create a new socket on that one and let the peered players connect to it.

Why would you need that? What could it do for you? Sure, it could take some load off the first server, but there are plenty of ways you could load-balance if that's the issue; doing it asymmetrically like this tends to lead to one server at 100% while the other one's at 5%…

Or maybe there is another way of doing this.

One obvious way is to not do anything. Just let them keeping talking to the same port they're already talking to, just attach a different handler (or a different state in the client state machine, or whatever; you haven't given us any clue how you're implementing your server). I don't know what you think you're getting out of "perfect isolation". But even if you want it to be a different process, you can just migrate the two client sockets over to the other process; there's no reason to make them connect to a new port.
Another way to do it is to get the server out of the way entirely—STUN or hole-punch them together and let them P2P the game protocol.
Anything in between those two extremes doesn't seem worth doing, unless you have some constraints you haven't explained.

OBS. I am not going to have the game running on the server to deal with cheaters for now. Because this will be to much load for the server cpu on my setup.

I'm guessing that if putting even minimal game logic on the server for cheat protection is too expensive, spinning off a separate process for every pair of clients may also be too expensive. Another reason not to do it.
Multi multiplayer server sockets in python