A connection problem

Hi all.Altough my need is not strictly-speaking an hardware one, I hope this is a right place to submit it. All my friends that have FSX can host or join a private multiplayer session, I can't. They are all on WinXP as I.I have no problem joining an FSInn, an FSHostClient or a Squakwin session but I just can't login onto someone's else private FSX session or have anyone join a session I host. When I try to login I get to the "Trying to connect" windows and get stuck there. It seams that others trying to join my session get the same.System here: WinXP SP2 with all updates, FSX SP2, all SDKs, E8400 CPU/2GB/GigabyteG31 MB/9600GT-NVIDIA 174.74. No router. So a setup equal/better that others use. It runs FSX fairly well with settings on the high side.Must be a bad setting/restriction somewhere in Windows/FSX/Internet connection. But WHERE?All suggestions are welcomed. Thanks in advance.Hugo