It is weird.
When you first connected, Dan couldn't so I rebooted my Modem, Router and Xbox.
Dan then got connected, but then you couldn't. So I am wondering if, it is something my end.
Then halfway throught the race with me and Dan my rounter rebooted itself. Not the first time it done that after being rebooted, so I am going to contact my ISP to see if they can send me another router or something, as they supplied the router in the begin.
While I am waiting for it, I am going to look at my router settings, as I have a race Tuesday and can't see me having a new one by then. Thought I have a feeling my ISP may have already sent me another one, so will look for that.
This is the first time I have had this happen while hosting a game, it was ok when I had Call of Duty Black Ops and Modern Warfare 2.
Just had a quick look at my router settings and I see
NAT Filtering is: Secured and not Open, it could be this that is the problem.
So on my next event I will turn it off and turn off the SPI firewall, which should help I hope.
Paulo please don't let this put you off of events I hold.