We are aware of the issue that some Halo 3 gamers receive a warning that their NAT (Network Address Translation) is not "Open" and is set to "Moderate" levels when performing network tests or attempting to connect to matchmaking sessions over Xbox Live. Due to the enterprise nature of the security infrastructure protecting our network, we are unable to correct this issue.

Please disregard this message, in our testing we have found there is no significant impact to user's performance on the Xbox Live network.