Methods and computer-readable media are provided to allow for the establishment of an Internet protocol (IP) data session with a dual-stack mobile communications device by authenticating the device. An IP data session is requested, and a home agent sends an indication of this request. A DNS server that will be assigned to a device is identified by querying a database and is identified based on the device's capabilities. The device capabilities are determined by a device-capability identifier that is associated with the user of the device or the device itself, such as a network access identifier. The capabilities may include the device type, applications, programs, or services that the user of the device is subscribed to, or capabilities that are inherent to the phone. Once the DNS server is identified, a server identifier is sent to the home agent, which assigns the DNS server to the device.