PowerDNS is a DNS server program, written in C++ and licensed under the GPL. It runs on most

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

derivatives. PowerDNS features a large number of different ''backends'' ranging from simple

BIND BIND () is a suite of software for interacting with the Domain Name System (DNS). Its most prominent component, named (pronounced ''name-dee'': , short for ''name daemon''), performs both of the main DNS server roles, acting as an authoritative ...

style zonefiles to

relational database A relational database is a (most commonly digital) database based on the relational model of data, as proposed by E. F. Codd in 1970. A system used to maintain relational databases is a relational database management system (RDBMS). Many relatio ...

s and load balancing/

failover Failover is switching to a redundant or standby computer server, system, hardware component or network upon the failure or abnormal termination of the previously active application, server, system, hardware component, or network in a computer n ...

algorithms In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ...

. A DNS recursor is provided as a separate program.

History

PowerDNS development began in 1999 and was originally a commercial proprietary product. In November 2002, the source code was made public under the open-source GPL v2 license.

Features

PowerDNS Authoritative Server (pdns_server) consists of a single core, and multiple dynamically loadable backends that run multi-threaded. The core handles all packet processing and DNS intelligence, while one or more backends deliver DNS records using arbitrary storage methods. Zone transfers and update notifications are supported, and the processes can run ''unprivileged'' and '' chrooted''. Various '' caches'' are maintained to speed up query processing. '' Run-time control'' is available through the pdns_control command, which allows reloading of separate zones, cache purges, zone notifications and dumps statistics in Multi Router Traffic Grapher /

rrdtool RRDtool (''round-robin database tool'') aims to handle time series data such as network bandwidth, temperatures or CPU load. The data is stored in a circular buffer based database, thus the system storage footprint remains constant over time. ...

format. Realtime information can also be obtained through the optional built-in

web server A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initi ...

. There are many independent projects to create management interfaces for PowerDNS.

DNSSEC

The PowerDNS Authoritative Server supports

DNSSEC The Domain Name System Security Extensions (DNSSEC) are a suite of extension specifications by the Internet Engineering Task Force (IETF) for securing data exchanged in the Domain Name System (DNS) in Internet Protocol (IP) networks. The protoco ...

as of version 3.0. While pre-signed zones can be served, it is also possible to perform online signing & key management. This has the upside of being relatively easy, but the downside that the cryptographic keying material is present on the servers itself (which is also true of any HTTPS server when not used with a HSM for example).

Recursor

PowerDNS Recursor (pdns_recursor) is a ''resolving'' DNS server, that runs as a separate process. This part of PowerDNS uses a combination of native threads and user-space threads, through the use of

Boost Boost, boosted or boosting may refer to: Science, technology and mathematics * Boost, positive manifold pressure in turbocharged engines * Boost (C++ libraries), a set of free peer-reviewed portable C++ libraries * Boost (material), a material b ...

and the MTasker library,MTasker
/ref> which is a simple cooperative multitasking library. It is also available as a standalone package. It does not have to run a pdns_server process as a gatekeeper for pdns_recursor, if the goal is simply to provide caching/recursing/resolving nameservice as running pdns_recursor on its own is even more efficient than behind the authoritative component. Support for

validation was added to the pdns_recursor in version 4.0.

References

External links