Net::DNS::Resolver::Programmable is a Net::DNS::Resolver
descendant class that allows a virtual DNS to be emulated
instead of querying the real DNS.  A set of static DNS
records may be supplied, or arbitrary code may be specified
as a means for retrieving DNS records, or even generating
them on the fly.

WWW: http://search.cpan.org/dist/Net-DNS-Resolver-Programmable/