"I See" said the blind man.
Ace, sorry I didn't look at this post before. I ran into some of the same issues, and it relates to (1) nat Routers and (2) Linksys "U-Turn" issues.
First, understand that FS2002 chats with the server on one port then switches to another (somewhere in the 2300-2400 range) for play time. Since your Computer talks to the server on one port, the other ports must be forwarded for the messages to get back to you.
You may also need to us something called DXPort from
http://www.puffinsoft.com. I use it to split the DX Port range into groups of 10 so each of the internal machines can have to proper ports forwarded.
After you have joined the game, your PC stops working in Client-Server mode, and starts working with Peer-to-peer. This means that when player 2 joins, you are sending him your information and he is sending you his. You also both send information to the FSHost, because it was written to run as a FS2002 client, aka another peer.
When your friends connect to your FS Host server, they come through the router, which manages the data back to the host (Ports forwarded, to something like 192.168.1.100). The server gets 'client information from each of them and uses that to tell the other players where to send the information. FShost's address is translated by the router, so ither players send all data to your external address.
Here's the gotcha....
When you connect to the server, Linksys can't deal well with the U-Turn (If you try to connect to your outside address.) This is a known problem, and it took me quite sometime to work through it with Linksys. I have a long list of emails based on this issue. Lnowing that you cannot connect to the external address, you have to connect via the internal address (192.168....) and the FSHost tells the other players to send data back to your internal address (i.e. 192.168.1.101). If you have more than one player inside, you'll see each other. All the other players will send data to some other internal subnet (if there even is one) and that data will never reach you. Thus no positions, so no local rendering of aircraft.
*** THis information has been compiled based on use of the Linksys BEFW11S4 version 1 router. I have not been able to us another version or model to test any potential fix or better behavior. LInksys information I have seen across the Web stated that future development for this unit/version would not progress since the Dec 2002 released patch. That was also the verbal expectation I received from Linksys support in Feb 2003.
If someone has multiple machines inside a firewalled router, and is able to use the external IP address to connect to FSHost (or any other DirectX game) I'd love to hear about it, as I will someday upgrade from this unit.