Because Ethernet bridging does not scale, most enterprise networks consist of small Ethernet-based subnets interconnected by IP routers. Although Ethernet's flat addressing and transparent bridging allow each subnet to run with minimal configuration, interconnecting subnets at the IP level introduces significant management overhead that increases with the size of the network. As an alternative, we propose a scalable and efficient zero-configuration enterprise (SEIZE) networking architecture. SEIZE provides plug-and-play capability via globally unique flat addressing, while ensuring scalability and efficiency through shortest-path routing and hash-based location resolution. Switches perform location resolution on demand and can cache the results to optimize routing paths and to reduce the number of location-resolution requests. We present a design overview of SEIZE and show that it attains the best of Ethernet and IP.