Microbrew Message Center is designed to be an immensely scalable mail platform supporting multiple users, multiple domains, and multiple mail servers. It is akin to iPlanet or post.office but is not as complex and uses open source software to perform mundane services such as Web and mail services.
PowerDNS Backend Development Kit allows a developer to code backends which can be loaded at runtime by PowerDNS, a nameserver that reads data from different backends. The stock distribution comes with MySQL and PostgreSQL and other backends. It is also possible to do failover, loadbalancing, and geodirection from a backend.
NovaDNS is a program to manage many BIND zonefiles (domains) from a user-friendly, Web-based GUI. The zones are stored in a MySQL database, maintained through the Web GUI, and are periodically generated from the database. User information is also stored in a MySQL database. Users can only maintain their own domains, while administrators can maintain all domains (zone files) on the server. This program is especially useful for large ISPs with many customers.
PHPresolver is a DNS resolver library written in pure PHP. It may help you code email address validity verification under the Win32/BeOS port of PHP because the current version has no support for DNS-related functions such as getmxrr() or checkdnsrr(). In addition, the library partially supports IPv6 address resolution.
Dixie DNS & DHCP Config Tool is a Web interface written in PHP for configuring and administering ISC bind and dhcp. It maintains a database with general DNS and DHCP information, and information about subnets and hosts. It produces config files, or sends dynamic DNS updates if DDNS is used on the server. It has simple DNS and DHCP live browsers, and can produce subzone files for MS Active Directory.
GNU Privacy Guard DNS Keyserver Client enables sending and retrieving OpenPGP keys with GnuPG to and from DNS-based keyservers. DNS-based keyservers offer several advantages over traditional HTTP-based ones, such as distributed caching, server fail-over, and geographical optimal server selection, etc.
Dyn2stat (dynamic to static) is a Web application that keeps your IP in a central database. Dyn2stat allows you to update your IP automatically and access it through your Web browser. You can also add shares (links to servers, folders, and files on your computer) and access them with a simple hyperlink.