djbdns

djbdns is a collection of Domain Name System (DNS) server software created by Daniel J. Bernstein. It's known for its focus on security, reliability, and simplicity in configuration. Instead of relying on a single monolithic daemon like BIND, djbdns comprises several smaller, independent programs that communicate with each other, following the principle of least privilege.

djbdns is designed to be resistant to common DNS attacks such as cache poisoning and denial-of-service attacks. It achieves this through features like transaction signatures (TSIG), and a design that isolates different functions to minimize the impact of a security breach.

The djbdns suite includes several core components:

• dnscache: A caching DNS server that can be configured as a recursive resolver. It verifies DNS responses to prevent cache poisoning.
• tinydns: An authoritative DNS server for publishing domain names and associated records. It uses a simple text-based database format.
• axfrdns: A zone transfer server, used for replicating DNS data between authoritative servers.
• walldns: A tool for distributing zone data to multiple tinydns servers.

Despite its security advantages, djbdns hasn't achieved widespread adoption comparable to BIND or other DNS server implementations. Some reasons for this include its licensing terms, the complexity of its configuration (which, while secure, can be challenging for new users), and the emergence of alternative DNS server software with improved features and broader community support. However, djbdns remains a significant contribution to the field of DNS and has influenced the design of other secure DNS implementations.