Easy to use DNS server and resolver for Ruby

 RubyDNS is a high-performance DNS server which can be easily integrated into
 other projects or used as a stand-alone daemon. By default it uses
 rule-based pattern matching. Results can be hard-coded, computed, fetched from
 a remote DNS server or fetched from a local cache, depending on requirements.
 .
 In addition, RubyDNS includes a high-performance asynchronous DNS resolver
 built on top of Celluloid. This module can be used by itself in client
 applications without using the full RubyDNS server stack.