Valtz is a simple tool that can be used for validating and filtering tinydns-data (djbdns) zonefiles. It can be used both as an error-finding tool by end users and by automated scripts to filter out errors. Additionally, it can be used to filter out domain-specific data that does not belong in a given file. Thus, importing zone information from third parties, semi-trusted parties, and sloppy users can be done without fear.
slapi-dnsnotify is a plugin for OpenLDAP or other LDAP servers. It watches for changes in the serial number of a DNS zone stored in the LDAP server, and notifies DNS slave servers to refresh their copy of the zone. It can also increment the serial number of a zone whenever changes in that zone are made.
RubyDNS is a high-performance DNS server that can be easily integrated into other projects or used as a stand-alone daemon (via RExec). 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 EventMachine. This module can be used by itself in client applications without using the full RubyDNS server stack.