pdns: Open Source Networking & Connectivity

What is pdns?

PowerDNS (pdns) is a single C++ source repository containing three distinct DNS products — the PowerDNS Authoritative Server, the PowerDNS Recursor, and dnsdist, a DNS load balancer — and it is aimed at network and infrastructure operators who run DNS themselves.

What it is

PowerDNS is an open-source DNS suite written in C++ and distributed under the GNU GPLv2, with copyright held by PowerDNS.COM BV and many contributors; the README directs readers to the NOTICE file for the exact licence and the exception that accompanies it. It sits in this registry's Infrastructure & Operations / Networking & Connectivity category and carries the topics authoritative, dns, dns-server, dnsdist, powerdns, powerdns-authoritative-server and recursor. All three components can be built from the one tree, but they are also released separately as .tar.bz2, .deb and .rpm packages, so an operator can take just the part of the suite that is needed. Documentation lives at doc.powerdns.com and the project homepage is powerdns.com.

The problem it solves is one of consolidation: authoritative serving, recursive resolution and DNS traffic distribution are usually handled by unrelated codebases, each with its own packaging, configuration and upgrade path, whereas PowerDNS maintains the three together. The Authoritative Server depends on Boost, OpenSSL and Lua, and it reads zone data through selectable backends, so the same server can work from BIND-style zone files, query MySQL through the gmysql module, query PostgreSQL through gpgsql, or hand queries to a pipe-backend compiled for runtime loading. That choice is made at build time with ./configure --with-modules="bind gmysql gpgsql"; bind and gmysql are built in by default when no module list is given.

Key capabilities

Three DNS roles in one repository: the PowerDNS Authoritative Server, the PowerDNS Recursor and dnsdist, described in the README as a DNS loadbalancer.
Pluggable backends chosen at configure time, including bind, gmysql, gpgsql and the pipe-backend, with bind and gmysql built in by default.
DNSSEC support for ed25519 (algorithm 15) when the Authoritative Server is built with --with-libsodium.
A geoip backend built against MaxMind's libmaxminddb libraries for location-derived answers.
Lua support throughout, including Lua records that can be switched off with --disable-lua-records.
systemd integration through --enable-systemd, which creates service scripts manageable with systemctl or service.
Packaging as .deb and .rpm packages, .tar.bz2 source releases, and Docker images documented in the repository's Docker-README.md.

Who uses it and how

Infrastructure teams serving authoritative zones from wherever the data already lives: BIND zone files, a MySQL or PostgreSQL database, or a custom pipe backend.
Operators who need DNSSEC signing, including the ed25519 algorithm, and therefore build with libsodium present.
Services that answer differently by client location, using the geoip backend together with MaxMind's database packages.
Sites running recursion for their own users through the PowerDNS Recursor, whose README sits in pdns/recursordist, or placing dnsdist in front of nameservers as a load balancer.
Teams that standardise on distribution packages, systemd units or the published Docker images rather than compiling C++ themselves.

Getting started

The README gives no single install command: the three products ship separately as .tar.bz2, .deb and .rpm packages, with Docker images covered in Docker-README.md. Building from git means cloning the repository, running git submodule init and git submodule update, then ./builder/build.sh, a docker-based process provided by pdns-builder, or configuring by hand with autoreconf -vi, ./configure and make.

How it compares

The facts name no paid products that PowerDNS replaces, and no comparable open-source projects either, so a product-by-product comparison could not be drawn honestly here. On the evidence available, it stands alone in this registry as the listing that covers an authoritative server, a recursor and a DNS load balancer from a single repository under the GPL-2.0 licence.

When to use it — and when not to

Building from source is a commitment: Boost, OpenSSL, Lua and a C++-2017 compiler, plus autoconf, automake, ragel, bison and flex for git builds, plus development headers for whichever backend is selected. Teams that want one small binary with no backend decisions to make, or that would rather not choose between package, container and source builds, are not the audience here. Two limitations are plain in the facts: the README warns that it may lag behind and defers to doc.powerdns.com for current information, and the licence's exact terms and exception live in the NOTICE file rather than the README, so they must be checked before redistribution; the repository also carries 932 open issues, which is worth weighing for anyone depending on prompt triage.

project readme (upstream, from github) — read inline

All documentation can be found on https://doc.powerdns.com/

This file may lag behind at times. For most recent updates, always check https://doc.powerdns.com/authoritative/changelog/

Another good place to look for information is: https://doc.powerdns.com/authoritative/appendices/compiling.html

To file bugs, head towards: https://github.com/PowerDNS/pdns/issues

But please check if the issue is already reported there first.

DOCKER

This README is mirrored from GitHub to dockerhub. For information about our Docker images, please refer to https://github.com/PowerDNS/pdns/blob/master/Docker-README.md

SOURCE CODE / GIT

Source code is available on GitHub:

git clone https://github.com/PowerDNS/pdns.git

This repository contains the sources for the PowerDNS Recursor, the PowerDNS Authoritative Server, and dnsdist (a powerful DNS loadbalancer). All three can be built from this repository. However, they are also released separately as .tar.bz2, .deb, and .rpm packages.

The different releases can be built by the help of pdns-builder, which uses a docker-based build process. To get started with this, run these commands in the root of this repository:

git submodule init
git submodule update
./builder/build.sh

This will bring up a USAGE-page which will explain how to build the different releases.

COMPILING Authoritative Server

The PowerDNS Authoritative Server depends on Boost, OpenSSL and Lua, and requires a compiler with C++-2017 support.

On Debian, the following is useful:

apt install g++ libboost-all-dev libtool make pkg-config default-libmysqlclient-dev libssl-dev libluajit-5.1-dev python3-venv

When building from git, the following packages are also required:

apt install autoconf automake ragel bison flex

For Ubuntu, the following packages should be installed:

apt install libcurl4-openssl-dev luajit lua-yaml-dev libyaml-cpp-dev libtolua-dev lua5.3 autoconf automake ragel bison flex g++ libboost-all-dev libtool make pkg-config libssl-dev lua-yaml-dev libyaml-cpp-dev libluajit-5.1-dev libcurl4 gawk libsqlite3-dev python3-venv
# For DNSSEC ed25519 (algorithm 15) support with --with-libsodium
apt install libsodium-dev
# If using the gmysql (Generic MySQL) backend
apt install default-libmysqlclient-dev
# If using the gpgsql (Generic PostgreSQL) backend
apt install libpq-dev
# If using --enable-systemd (will create the service scripts so it can be managed with systemctl/service)
apt install libsystemd0 libsystemd-dev
# If using the geoip backend
apt install libmaxminddb-dev libmaxminddb0 libgeoip1 libgeoip-dev

Then generate the configure file:

autoreconf -vi

To compile a very clean version, use:

./configure --with-modules="" --disable-lua-records
make
# make install

This generates a PowerDNS Authoritative Server binary with no modules built in.

See https://doc.powerdns.com/authoritative/backends/index.html for a list of available modules.

When ./configure is run without --with-modules, the bind and gmysql module are built-in by default and the pipe-backend is compiled for runtime loading.

To add multiple modules, try:

./configure --with-modules="bind gmysql gpgsql"

Note that you will need the development headers for PostgreSQL as well in this case.

See https://doc.powerdns.com/authoritative/appendices/compiling.html for more details.

If you run into C++11-related symbol trouble, please try passing CPPFLAGS=-D_GLIBCXX_USE_CXX11_ABI=0 (or 1) to ./configure to make sure you are compatible with the installed dependencies.

Compiling the Recursor

See README.md in pdns/recursordist/.

Compiling dnsdist

See README.md in pdns/dnsdistdist.

Building the HTML documentation

The HTML documentation (as seen on the PowerDNS docs site) is built from ReStructured Text (rst) files located in docs. They are compiled into HTML files using Sphinx, a documentation generator tool which is built in Python.

Install the dependencies under "COMPILING", and run autoreconf if you haven't already:

autoreconf -vi

Enter the docs folder, and use make to build the HTML docs.

cd docs
make html-docs

The HTML documentation will now be available in html-docs.

FreeBSD Notes

You need to compile using gmake - regular make only appears to work, but doesn't in fact. Use gmake, not make.

The clang compiler installed through FreeBSD's package manager does not expose all of the C++17 features needed under the default std=gnuc++14. Force the compiler to use std=c++17 mode instead.

export CXXFLAGS=-std=c++17

macOS Notes

PowerDNS Authoritative Server is available through Homebrew:

brew install pdns

If you want to compile yourself, the dependencies can be installed using Homebrew. You need to tell configure where to find OpenSSL, too.

brew install boost lua pkg-config ragel openssl
./configure --with-modules="" PKG_CONFIG_PATH=/usr/local/opt/openssl/lib/pkgconfig
make -j4

Additionally, for PostgreSQL support, run brew install postgresql and add --with-modules="gpgsql" to ./configure. For MySQL support, run brew install mariadb and add --with-modules="gmysql" to ./configure.

Linux notes

None really.

Frequently asked questions

Is pdns free to use?

pdns is open source under the GPL-2.0 licence. There is no licence fee and no seat count — you can self-host it or, where the project offers one, pay a vendor for a managed version instead.

What does pdns do?

PowerDNS Authoritative, PowerDNS Recursor, dnsdist

What is pdns written in?

pdns is primarily written in C++. Its source is publicly available at https://github.com/PowerDNS/pdns, and it has 4,473 GitHub stars.