Here's a rather interesting issue at hand. Any insight on this would be greatly apperciated. Let me start with this :

I can host, but my friend can not. We played just yesterday with him and another friend just fine. Today we were going to play some more just two of us, but we can't however.

When he tries to join my game.. It gets stuck on '' Waiting player information ''.. However on my side, I can see that he joined the server.. Although on his side he isn't on my server yet. This happens every single time we try now, and rebooting W:A has no difference for it.

Before you think that there is something wrong on my end.. Let me say this : I can still host. Everyone else can join my hosts and I can start games with them.

Also before you think it's on my friends end... : He can still join anyone else who hosts a game, but not me. Trying to use DirectIP for us to play results in connection loss instead of '' Waiting for player information ''

Any insight and help would be appreciated O.O.

However, that's not all. Something weird just happened.. Or so I think, anyway. I hosted the said DirectIP game.. My friend couldn't join yes.. However some guy called Zani90 from Italy joined that said game. I was in impression you can't join DirectIP games unless you go to the DirectIP screen and write the IP there. If that is true.. How on earth he could join my game.. It sounds unrealistic coincidence for him to grab my IP from somewhere and write it there on the exact moment.. Wasn't bug either as he talked to me.. Left, and came back couple mins later.

Thanks in advance for any info you can offer :<.

-Heart.

If you hosted a game on WormNet then anyone could have gotten your IP and joined slightly later when you hosted a private game.

Problems like the one you described happen when an Internet node has an MTU (http://en.wikipedia.org/wiki/Maximum_transmission_unit) limit lower than the size of a packet frame that your computer is trying to send, and the ICMP (http://en.wikipedia.org/wiki/Internet_Control_Message_Protocol) "Destination Unreachable (Datagram Too Big)" (http://en.wikipedia.org/wiki/ICMP_Destination_Unreachable) packet does not reach your computer (for example, due to a paranoid or over-zealously configured firewall). If you are unable to configure your firewall(s), the workaround is to reduce the MTU size (http://www.google.com/search?q=windows+set+mtu) for your/your friend's computer.

So which one of us needs to reduce the MTU size ? I don't even have a firewall so it's not on my side about the firewall atleast... And reduce to exactly what size ?

I can't know unless you both provided me with a packet log. And you'll have to experiment with the MTU size.

You're speaking of something I have no idea about. Even probably something '' so simple '' as packet logs. With that said, where do I get them ?

But still.. How can this exactly be the source of problem considering just few days ago we played fine and now it won't work O_o.

You'll probably have to blame one of your ISPs.

If you want me to tell you whose packets are getting lost, you should both install WireShark (http://www.wireshark.org/), and record a connection attempt, then post the logs. Use "tcp port 17011" as the packet filter to filter out unrelevant traffic.

Experimenting with the MTU size as in how ? I mean.. Do both of us need to have same size of MTU.. I really have no clue.. Even if you don't know what the size should be.. Something like.. Should we raise the size.. lower it, and with how much.. Like.. hundreds or what o.O

.. We'll try WireShark later on though.

The default is usually 1500, so you should lower it until it works. Try 500. You don't need to both have the same MTU.

That was definitely odd. My friend managed to disable his NAT, and now we can play just fine. He had NAT activated before when we were still able to play so I don't really see how did it even have anything to do with it o.O

Good thing is, is that it works. Topic can be closed, thanks for help though :).

Is your computer directly connected to the internet, or is it in a network? Did you have to forward ports to be able to host, or did it just work?

My computer is connected to a router, but NAT is disabled and IP is in bridged mode. I was able to host always anyway.. If you read my post, you'd realise that.

My friend wasn't able to host, but that's not even the problem of this topic.. And don't ask me what he did.. He just told me he disabled NAT and puff, he can host