The present invention provides an efficient way of resolving telephone numbers and other entity/device identifiers into Internet addresses as well as accommodating portability of those telephone numbers and other entity/device identifiers without having to substantially modify or rework the domain naming system (DNS) infrastructure or established number portability schemes. Self-contained, additional functionality is implemented on a DNS server which allows smooth IP address resolution of telephone numbers or other entity/device identifiers by taking advantage of existing portability databases without impacting the existing networks that create and maintain such portability databases.