I've had this problem ongoing for several months and would really like to just get it so I can connect to Steam somewhat reliably. I don't like having to boot everyone in my house off the internet in order to use it.. not exactly fair!
I hear all over the place you shouldn't even need to set up the ports and UPnP should handle it, but I just am not having any luck. The rest of the internet works with absolutely no problem.
I've gone through all the stuff the troubleshooting pages and searched around for anyone with a similar problem, though I'm not sure what properties on this router correspond to stateful inspection or dynamic packet filtering.. would the latter be QoS? Just in case I turned it off. So not totally sure if I've exhausted all of those.. I can't think of anything else to try...
My setup is DIR-655 router, windows firewall turned off, i'm plugged into the router with network cable going through a hub, and via wireless. my computer is a late 2008 macbook pro running windows 7 via bootcamp. I don't know if bootcamp could be the issue, but everything seems to see it as a normal windows machine.
I have Upnp turned on, and the correct ports set up to forward to the IP of my laptop (though am curious as to what it means when I have 2 IPs listed in the router config.. I'm assuming one is wired and one is wireless... is there a way to be sure which is which?)