Hey guys me and my buddy want to do the challenges together, can someone give me a hint on how we can do this. Because when i start the server up on my end and select it as "private" then i put the password in or dont put one in at all it keeps telling him on his end that the Server is not Responding, then it will do the samething to me if i try to join on him. We would like a good explanation why we cant run a private challenge server and have each other join through steam invite nor through ip address. Someone needs to address this problem for me, thanks and this can be treated as urgent as we're waiting to do the challenges before start into multiplayer gameply.

have you forwarded the proper ports on your router ?

thats what i need... can someone direct me on how to do this and waht the port numbers are?