pop-before-dyndns service using djbdns

 tinydyndns is a simple but powerful dynamic DNS solution that uses
 djbdns. It cooperates with the djbdns package to publish dynamic IP
 addresses authenticated through POP connections. On successfully
 authenticated POP connections, the tinydyndns-update program manipulates
 tinydns' constant database "data.cdb" directly without rebuilding it;
 this makes the dynamic DNS solution use very few system resources.
 .
 Using a POP service for authentication saves the work for installing
 special client software, since POP clients are available for every
 common network-aware operating system. To provide the DNS and POP
 services, tinydyndns cooperates with djbdns, mailfront, and cvm.
 .
 The POP service can easily be replaced with other services that provide
 authentication, such as APOP, IMAPS, ...