A modular meter based utility gateway enclosure which resides between a power meter and a meter socket of a residence or other building supports multiple interchangeable local area network (LAN) and wide area network (WAN) interface cards. As a result, multiple LAN and WAN media are simultaneously and interchangeably supported by simply changing interface cards inserted into the slots of the enclosure. The modular meter based utility gateway enclosure includes a WAN card slot for accepting a WAN interface card, multiple LAN card slots for respectively accepting LAN interface cards, and a data bus for enabling communication between the WAN interface card and the LAN interface cards inserted into the WAN and LAN card slots respectively. The modular meter based utility gateway enclosure may also support one or more interdiction cards, and may further include a tamper proof mechanism to prevent unauthorized tampering with the enclosure.