HsDns provides an asynchronous DNS resolver on top of GNU ADNS. Not all options are supported, but A, MX, and PTR lookups work nicely. There is also support for retrieving generic RR types, CNAMEs, and for NSEC zone walking. The library can be expected to work with fine ADNS 1.4 or later. It might also work with version ADNS 1.3, but that hasn’t been tested.