Problem: Sometimes when you try to connect your Xbox to the LIVE service on the LETU network, you get a message that says:
"Your NAT type is Moderate. People on networks with this NAT type may not be able to join certain games or hear other people while playing online. For the best online experience, you need an open NAT configuration."
Explanation: This relates to the way LETU's firewall translates the addresses and ports from one side to the other. According to Microsoft, it just limits with whom you can connect (other people with Moderate or Open NAT types). Some Xbox multiplayer games do work regardless of this connection warning, but others don't.
Resolution: There is currently no way to mitigate this error because of the way the Microsoft's LIVE service detects NAT types.
Reference: http://support.xbox.com/en-us/pages/xbox-360/troubleshoot/kb/error-your-nat-type-strict.aspx?kbid=979000
Reference: https://help.queens.edu/hc/en-us/articles/203055494-XBox-360-Warning-about-Moderate-or-Strict-NAT-Type