online

use mooclick.. my favorite...
just set ur local\remote ips...
connect to it on the same port u hosted... and there ya go (dont even have to sign on a channel if its just 2 players its server to client communication...)

Argh... you can't use MooClick, cause you need to send data through UDP port, since it's an action game, and MooClick doesn't support it (there's a bug which disallows you to do it).
You need to use MooGame, since it can send data using UDP ports. There are some examples on this community, showing how to use it.

shouldn't LANs be able to create a TCP connection? I had network class this year and we did it all the time. Why do you think he can't do it?

when he said "ips" he mean IPs (IP addresses)... That is a fixed (or dynamic) address that identifies your computer on network or internet...

I used a mooclick over LAN and it worked as it should... although I don't remember if we used a fixed-IP server or direct comm...

I didn't mean it won't work in LAN. Sending data through UDP doesn't work outside the LAN neither. MOOClick just has a bug that disables it and since it's an action game, he has to use UDP to send data faster, to prevent delays.

In a way, but not neccessarily... he just needs a good optimization technique for cutting the bandwith down... I don't know how he is doing his game so I can't tell any way that would work, but if they are playing on LAN, they shouldn't have much of a problem since sending data over LAN would (and should) be fast (and stable) enough to outweight the TCP overhead...

sending everything on every loop won't work either...

Well, if it's going to be used on the LAN only, then he can use the TCP
MOOGame is technically the same thing what MOOClick, so why not use it instead and make it work also outside the LAN?

You should also note that UDP is not secure protocol so there is no guarantee that the packet was received. Unless you implement your own way of communication over UDP, it is likely that some packets will drop out (much less over LAN then over internet)... You should keep that in mind when deciding what data you send over UDP and what over TCP.

Crucial data should ALWAYS be sent over TCP.

If for example, you send the players location over UDP and some packets miss or get delayed, you will see that as a lag. In this case, it may not be much of a problem. However, if you are sending chat message or say a player gives amount of gold (this is only for example) to another player, then it is important that the transaction actually takes place - UDP is very risky in the case.

I also believe that decent communication could be achieved using .NET extension if you are familiar with VB or C#.

I never used MooGame so I can't answer your last question. Sorry..

Rule of thumb. Always keep a sharp line between what is visual and what is behind the scenes. It's understandable that you want to keep both of them as in sync as possible, but critical information such as who did what damage is more important to keep in sync then assuring that it appeared like you hit the person.
If you put everything into making it look like you hit the person, then rely on local hits to do any damage, theres a sharp chance of you breaking sync anyway, because it's still possible for visual lag, especially with radius attacks that do different damages from different locations.

I made a few online action games and I can say that you MUST use UDP for sending movement. It is unsecured and there is no guarantee you'll receive it, SO you have to send data in a continuous loop.
Other things like HP, shooting, etc. need to be sent using TCP without any loop.
But we're a little off-topic now. There are some examples of using MOOGame on this community. You can check out my example showing how to make a simple action game using it (also available on this community).