sam,

The absolute answer is, "it depends".  

The first reason "it depends" is that the issue does not ALWAYS show up.  Sometimes when you connect with closed ports....... other ARE able to join.  That's weird... but it is the way it happens.  There is a lot of chatter on the multiplayer forums about this and Miocrosoft is aware of the issues ,.......abut has not currently suggested a solution.

The basic thing about the ports issue is that it usually does not affect YOU when your ports aren't opened correctly....... it affects OTHERS.

YOU get the effect when someone ELSE on the FSHost server does not have ports opened correctly.

So if you connect first.... you will be fine... but your unopened ports can keep someone else from connecting.  Or if there are others online already and you connect, your port issue may cause one or more of them to be "booted" off the connection.

Now part of the "it depends" issue is that some servers are apparently set up so that they will detect incorrct port situations and will not let you connect or will boot you off when they are detected.  Also if a server administrator is online.... he/she can scan ports and either talk to you about it or just boot you.

So for online flying with others it is a "common 'professional' courtesy" to make sure that your ports are set up right so that your actions do not prevent others from enjoying the flight too.  

While you need to open the ports in the firewall...... the exact #'s of which can vary depending on the particular server you are flying on .....the biggest issue is the router's ports.  Adding fs2004 and teamspeak's ports  to the "exceptions" list in WinXP is easy. Don't forget the ones for Teamspeak if you use that.

See the stickys at the top of the forum for help in getting the router / dsl / cable modem set up right.  There is plenty of info here in this forum to get things sorted out.  

Hope this helps.

best,

....................john

Thank´s for your replies !
We both have DX9 Installed.
It seems that FS9 Multiplayer is really a miracle.
Yesterday we both opened our ports as explained in
a lot of tutorials. And my friend tried to
open a Server but no matter what we did.
I couldn´t connect (I didn´t see his session at all). I red eno´s posts in this forum, I found the official microsoft document and red several other tutorials... without success.
Than I somehow came across this site http://www.airflyers.net/ where they instruct you to open
UDP 2302-2400 as well. After opening these ports suddenly it worked very well ! I wonder that no other site not even MS writes anything about these ports.

However.. in my opinion I think it´s a very bad idea to solve a Multiplayer connection the way FS9 does it.
To me it looks like this is more a peer to peer network
than a client server connection (obviously). The server probabely just handles you over to other users. I mean it would make sence if you have 10000 people flying in one session.
But for a normal network game of that size .. it doesn´t make sence at all. Nowadays the multiplayer parts of newer games work rocksolid !!

I have 3 further questions regarding multiplayer.

1. Why can´t I see the animations of
other players aircraft ?
We both made shure that the option is activated in the multiplayer settings. But we don´t see flaps, rudder,
engines, reverse thrust, main door etc.... Actually we tested with the default lear45.
Probabely I have to open an extra port for this to work ?
 

2. You can assign a button in Multiplayer Section "Follow other Player". I would think if you hit it you get a spotplane view of the other network player. But it doesn´t . What is it supposed to do ?

3. When you get a little further away of another players
aircraft.. it starts jumping around  in the sky.. or on the ground. Can you somehow tweak the range you see other players aircraft without jumping ?

cheers

As John said ....... the jumping is due to data transfer differences.

Animations ....... some show ....... some don't ..... its just the way it is.

To warp quickly to another player ... ctrl+shift +i ( could be t it's late and I'm tired) to bring up the players name.... then Ctrl+Shift+f to warp to them. Other than that I don't remember seeing anything about following another player.