I can't seem to get NAT Type Open in MW3. uPnP is enabled and uPnP status says that that UDP3074 is forwarded to my computer, but no go:
3074 keep state udp (this PC's IP) DemonwarePortMapping
I've pretty much isolated the issue to the firewall, or at least some MW3->firewall combo, since I tested with a Cisco/LinkSys modem/router (also tried with just the router part connected to my regular modem) and then I got NAT Type Open. Cisco/linksys logs say:
Mon, 2011-11-28 20:10:25 - Returning UPnPError 714: NoSuchEntryInArray
Mon, 2011-11-28 20:10:25 - AddPortMapping: external NULL:3074 to (this PC's IP):3074 protocol UDP for: DemonwarePortMapping with timeout:0
Mon, 2011-11-28 20:10:25 - no permission rule matched : accept by default (n_perms=0)
Mon, 2011-11-28 20:10:25 - redirecting port 3074 to (this PC's IP):3074 protocol UDP for: DemonwarePortMapping
Mon, 2011-11-28 20:10:25 - creating pass rule to (this PC's IP):3074 protocol UDP for: DemonwarePortMapping
The strange bit is that MW2 works, along with "everything else" that uses uPnP.
Please help me out here, I'm running out of hope...