gdnsd is an Authoritative-only DNS server. The initial g stands for Geographic, as gdnsd offers a plugin system for geographic (or other sorts of) balancing, redirection, and service-state-conscious failover. The plugin system can also do things like weighted address/cname records. If you don't care about these features you can ignore them :).
gdnsd is written in C, and uses pthreads with libev and liburcu to attain very high performance, low latency service. It does not offer any form of caching or recursive service, and does not support DNSSEC. There's a strong focus on making the code efficient, lean, and resilient. The code has a decent regression testsuite with full branch coverage on the core packet parsing and generation code, and some scripted QA tools for e.g. valgrind validation, clang-analyzer, etc.
The geographically-aware features also support the EDNS Client Subnet spec from RFC 7871 for receiving more-precise network location information from intermediate shared caches.
Project site: https://gdnsd.org/
Release downloads: https://github.com/gdnsd/gdnsd/releases/
The code is hosted at Github: https://github.com/gdnsd/gdnsd/
Bug reports: https://github.com/gdnsd/gdnsd/issues
Wikified docs: https://github.com/gdnsd/gdnsd/wiki
Google Group for discussion: https://groups.google.com/forum/#!forum/gdnsd
See the INSTALL file for details on prerequisites and build procedure for working from the source tree or a source tarball.
The documentation is included in the source tree in POD format and installed as manpages and textfiles on installation.
COPYRIGHT AND LICENSING
gdnsd is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
gdnsd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with gdnsd. If not, see http://www.gnu.org/licenses/.