Port Question

[Dar Scott]

On Thursday, February 5, 2004, at 10:31 PM, Scott Rossi wrote:

> All the routers I've owned allow you to assign one system on the 
> network a
> DMZ (demilitarized zone) address which I believe allows pretty much any
> traffic in and out.  Maybe this is what has to be set up by the game
> players.

Other routers have ways to set up something similar (fixed NAT with 
open rules).

This has the advantage in that one computer behind each firewall can 
act as a game communications concentrator.

I find the idea of peer-to-peer communications very interesting.  I 
think the firewall is one of the potential problems.

I had suggested the idea of a server or servers.  If you want to 
preserve the notion of peer-to-peer, maybe the server is for 
facilitating communications only.  And for setting up games among those 
looking for players.  Once a game is created then the game server might 
then only facilitate game memo distribution and throttling 
denial-of-service.

The simplest way is to have all game instances go through the server in 
communication, but you might find some performance shortcuts to be used 
later.

One of the problems with going to port 80 is that some firewalls will 
force this to go through a proxy server and force the protocol to be 
http only.  Many firewalls are set up to allow tcp going to other ports 
but only if originated from the LAN, that is, from inside.

The method least likely to cause trouble with firewalls might be to 
make bonafide http connections from inside to outside.  If that has 
performance problems then eventually the game might try some other link 
to the server or try to make a direct connection and if those fail, 
drop down to http to a server.

I designed Revolution based communications system last year in which a 
server and many clients sent little messages to each other, but this 
peer-to-peer communications was facilitated by a star-shaped shell 
created by clients making tcp connections to the server, even through 
firewalls.  So, even though communication was peer-to-peer at some 
level, the connection was client-server.

Dar Scott