US Patent 10496993 DNS-based device geolocation

In various situations, it may be desirable to know the location of a device requesting services, and to confirm that the device is at an actual location that coincides with the purported location of the device. In order to verify that a device is actually at its purported location, the device may be instructed to perform DNS (domain name system) lookups to resolve a set of given network domain names and to thereby find network addresses that are associated with the domain names Geolocation databases are then consulted to determine the locations of the hosts associated with the network addresses. These locations are checked for consistency with the purported location of the device, and services may be denied if inconsistencies are found.