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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Chapter 1. The PowerDNS dynamic nameserver</title><link rel="stylesheet" href="docbook.css" type="text/css" /><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="PowerDNS manual" /><link rel="up" href="index.html" title="PowerDNS manual" /><link rel="prev" href="index.html" title="PowerDNS manual" /><link rel="next" href="about.html" title="2. About this document" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 1. The PowerDNS dynamic nameserver</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="index.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="about.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 1. The PowerDNS dynamic nameserver"><div class="titlepage"><div><div><h2 class="title"><a id="powerdns"></a>Chapter 1. The PowerDNS dynamic nameserver</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="powerdns.html#function-design">1. Function & design of PDNS</a></span></dt><dt><span class="sect1"><a href="about.html">2. About this document</a></span></dt><dt><span class="sect1"><a href="changelog.html">3. Release notes</a></span></dt><dd><dl><dt><span class="sect2"><a href="changelog.html#changelog-auth-3-2">3.1. PowerDNS Authoritative Server 3.2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-3-1">3.2. PowerDNS Authoritative Server 3.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-2-9-22-6">3.3. Authoritative Server version 2.9.22.6</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-2-9-22-5">3.4. Authoritative Server version 2.9.22.5</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-3-0-1">3.5. PowerDNS Authoritative Server 3.0.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-3-0">3.6. PowerDNS Authoritative Server 3.0</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-3-1">3.7. Recursor version 3.3.1 </a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-3">3.8. Recursor version 3.3 </a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-2">3.9. Recursor version 3.2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-7-2">3.10. Recursor version 3.1.7.2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-7-1">3.11. Recursor version 3.1.7.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-2-9-22">3.12. Authoritative Server version 2.9.22</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-2-9-21-2">3.13. Authoritative Server version 2.9.21.2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-auth-2-9-21-1">3.14. Authoritative Server version 2.9.21.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-7">3.15. Recursor version 3.1.7</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-6">3.16. Recursor version 3.1.6</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-5">3.17. Recursor version 3.1.5</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-21">3.18. PowerDNS Authoritative Server version 2.9.21</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-4">3.19. Recursor version 3.1.4</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-3">3.20. Recursor version 3.1.3</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-2">3.21. Recursor version 3.1.2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-1-1">3.22. Recursor version 3.1.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-0-1">3.23. Recursor version 3.0.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-recursor-3-0">3.24. Recursor version 3.0</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-20">3.25. Version 2.9.20</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-19">3.26. Version 2.9.19</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-18">3.27. Version 2.9.18</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-17">3.28. Version 2.9.17</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-16">3.29. Version 2.9.16</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-15">3.30. Version 2.9.15</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-14">3.31. Version 2.9.14</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-13">3.32. Version 2.9.13</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-12">3.33. Version 2.9.12</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-11">3.34. Version 2.9.11</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-10">3.35. Version 2.9.10</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-8">3.36. Version 2.9.8</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-7">3.37. Version 2.9.7</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-6">3.38. Version 2.9.6</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-5">3.39. Version 2.9.5</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-4">3.40. Version 2.9.4</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-3">3.41. Version 2.9.3a</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-2">3.42. Version 2.9.2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9-1">3.43. Version 2.9.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-9">3.44. Version 2.9</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-8">3.45. Version 2.8</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-7">3.46. Version 2.7 and 2.7.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-6-1">3.47. Version 2.6.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-6">3.48. Version 2.6</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-5-1">3.49. Version 2.5.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-5">3.50. Version 2.5</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-4">3.51. Version 2.4</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-3">3.52. Version 2.3</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-2">3.53. Version 2.2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-1">3.54. Version 2.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-0-1">3.55. Version 2.0.1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-0">3.56. Version 2.0</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-0-rc2">3.57. Version 2.0 Release Candidate 2</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-2-0-rc1">3.58. Version 2.0 Release Candidate 1</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-1-99-12">3.59. Version 1.99.12 Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-1-99-11">3.60. Version 1.99.11 Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-1-99-10">3.61. Version 1.99.10 Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-1-99-9">3.62. Version 1.99.9 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-1-99-8">3.63. Version 1.99.8 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#changelog-1-99-7">3.64. Version 1.99.7 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#idp7473920">3.65. Version 1.99.6 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#idp7487696">3.66. Version 1.99.5 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#idp7505760">3.67. Version 1.99.4 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#idp7524240">3.68. Version 1.99.3 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#idp7541440">3.69. Version 1.99.2 Early Access Prerelease</a></span></dt><dt><span class="sect2"><a href="changelog.html#idp7564112">3.70. Version 1.99.1 Early Access Prerelease</a></span></dt></dl></dd><dt><span class="sect1"><a href="security-policy.html">4. Security</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2006-01.html">5. PowerDNS Security Advisory 2006-01: Malformed TCP queries can lead to a buffer overflow which might be exploitable</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2006-02.html">6. PowerDNS Security Advisory 2006-02: Zero second CNAME TTLs can make PowerDNS exhaust allocated stack space, and crash</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2008-01.html">7. PowerDNS Security Advisory 2008-01: System random generator can be predicted, leading to the potential to 'spoof' PowerDNS Recursor</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2008-02.html">8. PowerDNS Security Advisory 2008-02: By not responding to certain queries, domains become easier to spoof</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2008-03.html">9. PowerDNS Security Advisory 2008-02: Some PowerDNS Configurations can be forced to restart remotely</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2010-01.html">10. PowerDNS Security Advisory 2010-01: PowerDNS Recursor up to and including 3.1.7.1 can be brought down and probably exploited</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2010-02.html">11. PowerDNS Security Advisory 2010-02: PowerDNS Recursor up to and including 3.1.7.1 can be spoofed into accepting bogus data</a></span></dt><dt><span class="sect1"><a href="powerdns-advisory-2012-01.html">12. PowerDNS Security Advisory 2012-01: PowerDNS Authoritative Server can be caused to generate a traffic loop</a></span></dt><dt><span class="sect1"><a href="thanks-to.html">13. Acknowledgements</a></span></dt></dl></div><p>
The PowerDNS daemon is a versatile nameserver which supports a large number
of backends. These backends can either be <a class="link" href="bindbackend.html" title="7. Bind zone file backend">plain zone files</a> or be
<a class="link" href="backends-detail.html#pipebackend" title="1. PipeBackend">more dynamic</a> in nature. Additionally, through use of clever programming techniques,
PowerDNS offers very high domain resolution performance.
</p><p>
Prime examples of backends include relational databases, but also (geographical) load balancing and failover algorithms.
</p><p>
The company is called PowerDNS.COM BV, the nameserver daemon is called PDNS.
</p><div class="sect1" title="1. Function & design of PDNS"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="function-design"></a>1. Function & design of PDNS</h2></div></div></div><p>
PowerDNS consists of two parts: the Authoritative Server and the Recursor. Other nameservers
fully combine these functions, PowerDNS offers them separately, but can mix both authoritative and recursive
usage seamlessly.
The Authoritative Server will answer questions about domains it knows about,
but will not go out on the net to resolve queries about other domains. However, it can use a
<a class="link" href="recursion.html" title="Chapter 16. Recursion">recursing backend</a> to provide that functionality. Depending
on your needs, this backend can either be the PowerDNS recursor or an external one.
</p><p>
When the Authoritative Server answers a question, it comes out of the database, and can be trusted as being authoritative. There is
no way to pollute the cache or to confuse the daemon.
</p><p>
The Recursor, conversely, by default has no knowledge of domains itself, but will always consult other authoritative servers
to answer questions given to it.
</p><p>
PDNS has been designed to serve both the needs of small installations by being easy to setup, as well as
for serving very large query volumes on large numbers of domains.
</p><p>
Another prime goal is <a class="link" href="security.html" title="Chapter 7. Security settings & considerations">security</a>. By the use of language features, the PDNS source code
is very small (in the order of 10.000 lines) which makes auditing easy. In the same way, library features have been used
to mitigate the risks of buffer overflows.
</p><p>
Finally, PDNS is able to give a lot of <a class="link" href="monitoring.html" title="Chapter 6. Logging & Monitoring Authoritative Server performance">statistics</a> on its operation which is both helpful in
determining the scalability of an installation as well as for spotting problems.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="index.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="about.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">PowerDNS manual </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 2. About this document</td></tr></table></div></body></html>
