My brother gets disconnected when he joins a server in steam. I've tried everything, port forward, run as admin (both steam.exe and "game.exe", turned of firewalls in windows and router...
Now comes the stranges thing, HE CAN JOIN WHEN I HOST!.. But that's the only server he can access..
He's on Windows 7 86-bit and I'm on Windows XP 32-bits.
Sometimes he takes his computer to my appartment (No we're not on local XD! He lives 10 miles from here) and maybe that's why his computer reconize my ip or something like that?
I hope I've got all the information you needed to solve this problem, thanks!
And oh, I'm from sweden, sorry about my bad english!