Overview

djbdns is a collection of Domain Name System tools. It includes software for all the fundamental DNS operations:

DNS cache: finding addresses of Internet hosts. When a browser wants to contact www.hotwired.com, it first asks a DNS cache, such as djbdns's dnscache, to find the IP address of www.hotwired.com. Internet service providers run dnscache to find IP addresses requested by their customers. If you're running a home computer or a workstation, you can run your own dnscache to speed up your web browsing.
DNS server: publishing addresses of Internet hosts. The IP address of www.hotwired.com is published by HotWired's DNS servers. djbdns includes a general-purpose DNS server, tinydns; network administrators run tinydns to publish the IP addresses of their computers. djbdns also includes special-purpose servers for publishing DNS walls and RBLs.
DNS client: talking to a DNS cache. djbdns includes a DNS client C library and several command-line DNS client utilities. Programmers use these tools to send requests to DNS caches.

djbdns also includes several DNS debugging tools, notably dnstrace, which administrators use to diagnose misconfigured remote servers.