pdnsd is a Proxy DNS server for Linux and FreeBSD that is designed to cope with unreacheable nameservers (e.g. because the dial-in link is not up) in a graceful manner to prevent DNS-dependent applications like Netscape from hanging. It has a permanent disk cache (i.e. the cache contents are saved in a file on exit) and supports parallel query and a wide variety of link uptests. It also has the ability to serve some types of locally defined records.