I tried a port under 1024 but it didnt worked. If i host no others can join. However when i go to the site i can see my game. When i join i can also see people chatting and at the list i can see the pings (no problem with the ping, sometimes its like 35). I have also played some online games. And McAfee firewall isnt blocking jazzjackrabit, i went to advanced options there and enabled jazz jackrabit outgoing and ingoing things. I dont know about ISP or modem.

EDIT: I also see some people saying hamachi, do you think it will work if i use hamachi? And how does it work? (However i dont think that many ppl are using it, just want to know if it works)
another EDIT: Woohoo! I used hamachi to log in into the server named: The Server and it worked