nsd

NSD is an acronym that can refer to several things, most notably in computing to the Name Server Daemon, an open-source authoritative DNS server. It is developed by NLnet Labs and released under a BSD-style license. NSD is designed to be fast, compact, and secure, focusing on serving zone data for domain namespaces rather than performing recursive lookups for end users.

As an authoritative server, NSD answers queries based on the zones it is configured to serve. It accepts DNS responses over UDP and TCP on the standard port 53 and supports serving zones that are signed with DNSSEC. The software supports standard zone transfers such as AXFR and incremental transfers (IXFR) to secondary servers, aiding zone synchronization. NSD is implemented in the C programming language and emphasizes a small memory footprint and straightforward auditing, which contribute to its reliability in high-volume environments.

NSD is primarily used on Unix-like operating systems and is commonly employed by organizations that require a lightweight, high-performance authoritative DNS server as part of a larger DNS infrastructure, sometimes alongside caching resolvers.

The NSD acronym can also refer to other organizations and concepts. For example, in the United States the National Security Division of the Department of Justice is abbreviated NSD, a unit responsible for national security and related civil rights enforcement; other entities may likewise use the acronym NSD.