1. Proxy DNS Server pdnsd is a 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. Some Netscape Navigator versions for Unix, for example, expose this behaviour. And it's IPv6 capable. From Debian 3.0r0 APT