pdnsd is a proxy DNS daemon with permanent (disk-)cache and the ability to serve local records. It is designed to detect network outages or hangups and to prevent DNS-dependent applications like Netscape Navigator from hanging.
The original author of pdnsd is Thomas Moestl, but pdnsd is no longer maintained by him. This is an extensively revised version by Paul A. Rombouts. For a description of the changes see http://www.phys.uu.nl/~rombouts/pdnsd.html and the file README.par in /usr/share/doc/pdnsd-1.2.9a