1. A computer implemented network security and fraud detection and prevention method for a system with one or more network service providers that provides a service and a network device that connects to at least one of the network service providers over a communications network to use the provided service, the method comprising: gathering information about the network device to generate a device identifier that identifies the network device; storing the device identifier in the database; associating the device identifier with and one or more reputation factors to generate a reputation of the network device; and sharing the reputation of the network device between the one or more network service providers to detect fraud using the network device across the network service providers.