<?xml version='1.0'?>

<reference anchor='RFC2308'>

<front>
<title abbrev='DNS NCACHE'>Negative Caching of DNS Queries (DNS NCACHE)</title>
<author initials='M.' surname='Andrews' fullname='Mark Andrews'>
<organization>CSIRO - Mathematical and Information Sciences</organization>
<address>
<postal>
<street>Locked Bag 17</street>
<street>North Ryde NSW 2113</street>
<country>AUSTRALIA</country></postal>
<phone>+61 2 9325 3148</phone>
<email>Mark.Andrews@cmis.csiro.au</email></address></author>
<date month='March' year='1998' />
<area>Applications</area>
<keyword>domain name system</keyword>
<keyword>DNS</keyword>
<abstract>
<t>

   [RFC1034] provided a description of how to cache negative responses.

   It however had a fundamental flaw in that it did not allow a name

   server to hand out those cached responses to other resolvers, thereby

   greatly reducing the effect of the caching.  This document addresses

   issues raise in the light of experience and replaces [RFC1034 Section

   4.3.4].
</t>
<t>



   Negative caching was an optional part of the DNS specification and

   deals with the caching of the non-existence of an RRset [RFC2181] or

   domain name.

</t>
<t>


   Negative caching is useful as it reduces the response time for

   negative answers.  It also reduces the number of messages that have

   to be sent between resolvers and name servers hence overall network

   traffic.  A large proportion of DNS traffic on the Internet could be

   eliminated if all resolvers implemented negative caching.  With this

   in mind negative caching should no longer be seen as an optional part

   of a DNS resolver.
</t></abstract></front>

<seriesInfo name='RFC' value='2308' />
<format type='HTML' octets='50045' target='http://xml.resource.org/public/rfc/html/rfc2308.html' />
<format type='XML' octets='41355' target='http://xml.resource.org/public/rfc/xml/rfc2308.xml' />
</reference>
