pdnsd, is an IPv6 capable proxy DNS server with permanent caching (the cache contents are written to hard disk on exit) that is designed to cope with unreachable or down DNS servers (for example in dial-in networking). . pdnsd can be used with applications that do dns lookups, eg on startup, and can't be configured to change that behaviour, to prevent the often minute-long hangs (or even crashes) that result from stalled dns queries.
