What is NAT?

NAT stands for Network Address Transalation. NAT works as an interface between LAN(Local area network) or WLAN(Wireless LAN) and WAN(Internet). If the NAT is blocked(by default) no incoming and outgoing communication between LAN/WLAN and WAN can be done.

Once NAT is open there are security levels created by NAT to restrict the communication between LAN (eg. XBOX conncted to a MIFI device) and WAN (Internet) which can be minimized by opening or forwarding certain ports. This also needs enabling  of UPnP and DMZ on the mifi device.

Alternatively NAT can be opened or the NAT security can be made moderate by assigning a static ip address to the device in LAN(XBOX360, PS3 etc.) and the ports can be opened for the same ip address on the mifi device(E5830, E585 & E586)interface.