fdnsname - resolve an IPv4 or IPv6 address to a hostname
fdnsname <IP address>
fdnsname will attempt to look up a single hostname for IP address
(which is an IPv4 address in dotted-quad format or an IPv6 address in
colon-seperated format). If one is found, it is printed to standard
output and the program exits with return code 0. If not, nothing is
printed and the program exits with return code 1.
Ian Gulliver <firstname.lastname@example.org>