Thank you!
It's my understanding that Call of Duty multiplayer falls back on peer connections when it can't find you a match, so I do see a mix of peer and server connections. That said, the Heatmap is usually pretty accurate and If it says there's a server there, I get games on it. I also keep them fenced in but peer connections get through in the marked area. However, the Heatmap for Modern Warfare 2 says there isn't a dedicated server in, say, Buffalo, NY but I get peer connections there, or at least what I can reasonably assume is a peer and not a server. Evey time I come across one I add it to my deny list. Problem is my Deny list is getting fairly long.
Since you mentioned it I'll keep a closer on connection addresses and see if I can find any kind of pattern to possibly identify a sever vs a peer.