299:) are usually recursive resolvers that store DNS query results for a period of time determined in the configuration (time-to-live) of each domain-name record. DNS caches improve the efficiency of the DNS by reducing DNS traffic across the Internet, and by reducing load on authoritative name-servers, particularly root name-servers. Because they can answer questions more quickly, they also increase the performance of end-user applications that use the DNS.
110:(ICANN). DNS servers, which are located all over the world, translate domain names into IP addresses, giving them control over which server a user may access via a given domain. Below the root, Internet resources are organized into a hierarchy of domains, administered by the respective registrars and domain name holders. A DNS name server is a server that stores the
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Caching name servers are often also recursive name servers—they perform every step necessary to answer any DNS query they receive. To do this the name server queries each authoritative name-server in turn, starting from the DNS root zone. It continues until it reaches the authoritative server for the
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containing the zone. The domain registry in turn configures the authoritative name servers for that top-level domain with delegations for each server for the zone. If the fully qualified domain name of any name server for a zone appears within that zone, the zone administrator provides IP addresses
172:
server. A primary server for a zone is the server that stores the definitive versions of all records in that zone. It is identified in the start-of-authority (SOA) resource record. A secondary server for a zone uses an automatic updating mechanism to maintain an identical copy of the primary
102:: the domain name hierarchy and the IP address system. The Domain Name System maintains the domain namespace and provides translation services between these two namespaces. Internet name servers implement the Domain Name System. The top hierarchy of the Domain Name System is served by the
307:
then returns this response to the client that asked the question. The authority, resolving and caching functions can all be present in a DNS server implementation, but this is not required: a DNS server can implement any one of these functions alone, without implementing the others.
246:(sometimes called a Recursive Name Server) is a DNS name server that accepts recursive queries (defined below) from clients (who are using a stub resolver), and then resolves those queries, either from a cache of prior results, or by asking one or more authoritative servers.
177:
and file transfer protocols. DNS provides a mechanism whereby the primary for a zone can notify all the known secondaries for that zone when the contents of the zone have changed. The contents of a zone are either manually configured by an administrator, or managed using
201:, the zone administrator provides the list of name servers (typically at least two, for redundancy) that are authoritative for the zone that contains the domain. The registrar provides the names of these servers to the
189:
of the authoritative name servers of a zone are listed in the NS records of that zone. If the server for a zone is not also authoritative for its parent zone, the server for the parent zone must be configured with a
230:) bit in the response to a query on a name for which it is authoritative. Name servers providing answers for which they are not authoritative (for example, name servers for parent zones) do not set the
53:. It translates an often humanly meaningful, text-based identifier to a system-internal, often numeric identification or addressing component. This service is performed by the server in response to a
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In principle, authoritative name servers suffice for the operation of the
Internet. However, with only authoritative name-servers operating, every DNS query must start with recursive queries at the
260:
If a name server cannot answer a query because it does not contain an entry for the host in its DNS cache, it may recursively query name servers higher up in the hierarchy. This is known as a
161:. An authoritative-only name server returns answers only to queries about domain names in that it is responsible for (as specifically configured by its administrator).
107:
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84:(IP) addresses, the second principal name space of the Internet which is used to identify and locate computer systems and resources on the Internet.
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zone that contains the queried domain name. That server provides the answer to the question, or definitively says it can't be answered, and the
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114:, such as address (A, AAAA) records, name server (NS) records, and mail exchanger (MX) records for a domain name (see also
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ncsd cache the results of DNS lookups but it also wraps the library routines that access information from the
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of the Domain Name System and each user system must implement resolver software capable of recursive operation.
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recursive, if they are configured to give authoritative answers to queries in some zones, while acting as a
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routers implement caching resolvers to improve efficiency in the local network. Some systems utilize
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72:. The most important function of DNS servers is the translation (resolution) of human-memorable
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Every domain name appears in a zone served by one or more authoritative name servers. The
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436:, Information Sciences Institute, J. Postel (Ed.), The Internet Society (September 1981)
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645:"Composite Application Manager for Internet Service Monitoring, Reference Guide"
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214:; otherwise, the delegation consists of the list of NS records for that zone.
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Although not the usual practice today, name servers can be both authoritative
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An authoritative name server is a name server that is responsible for giving
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typically provide caching resolvers for their customers. In addition, many
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A name server indicates that its response is authoritative by setting the
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Yakov
Rekhter; Susan Thomson; Jim Bound; Paul Vixie (April 1007).
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server's database for a zone. Examples of such mechanisms include
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Paul
Hoffman; Andrew Sullivan; Kazunori Fujiwara (January 2019).
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for that name server, which are installed in the parent zone as
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Internet
Protocol—DARPA Internet Program Protocol Specification
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118:) and responds with answers to queries against its database.
688:, though this is typically not used for caching DNS names.
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An example of a name server is the server component of the
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699:(2 ed.). Addison-Wesley Professional. p. 504e.
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Dynamic
Updates in the Domain Name System (DNS Update)
452:, P. Mockapetris, The Internet Society (November 1987)
423:, P. Mockapetris, The Internet Society (November 1987)
320:, which stands for the "name service caching daemon".
268:. A server providing recursive queries is known as a
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450:
30:
For protocol NAMESERVER that has been replaced with
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774:by Tim Fisher, retrieved on 2015-02-08 21-59 UTC
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157:in response to questions asked about names in a
667:"Network setup for Cambridge's new DNS servers"
725:files and their network database equivalents.
602:Domain Names - Domain Concepts and Facilities
164:An authoritative name server can either be a
49:for providing responses to queries against a
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45:is a computer application that implements a
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582:"Name Server definition at techterms.com"
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804:Internet Protocol based network software
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539:Clarifications to the DNS Specification
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14:
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345:Domain Name System Security Extensions
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693:; Snyder, Garth; Heine, Tra. (2006).
677:The recursive DNS server (aka recdns)
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350:Lightweight Directory Access Protocol
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98:The Internet maintains two principal
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536:Robert Elz; Randy Bush (July 1997).
421:Domain Names—Concepts and Facilities
27:Computer hardware or software server
197:When a domain is registered with a
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595:Paul Mockapetris (November 1987).
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335:Comparison of DNS server software
126:Name servers are usually either
106:maintained by delegation by the
64:(DNS), one of the two principal
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80:into the corresponding numeric
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36:ARPA Host Name Server Protocol
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1:
696:Linux administration handbook
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402:Public recursive name servers
397:List of managed DNS providers
256:Public recursive name server
187:fully qualified domain names
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761:Free and Public DNS Servers
355:Network Information Service
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276:, sometimes abbreviated as
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597:"Technical considerations"
310:Internet service providers
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29:
149:Authoritative name server
778:DNS & BIND Resources
387:Open Root Server Network
134:, as described below.
116:List of DNS record types
340:Trojan.Win32.DNSChanger
295:Caching name servers (
270:recursive name server
199:domain name registrar
145:for all other zones.
122:Types of name servers
224:Authoritative Answer
218:Authoritative answer
609:. sec. 4.2.1.
360:Name Service Switch
291:Caching name server
143:caching name server
809:Domain Name System
783:2006-09-02 at the
766:2016-10-15 at the
244:Recursive Resolver
238:Recursive Resolver
175:DNS zone transfers
94:Domain Name System
88:Domain name server
62:Domain Name System
706:978-0-13-148004-9
104:root name servers
82:Internet Protocol
51:directory service
16:(Redirected from
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314:home-networking
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92:Main article:
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74:domain names
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691:Nemeth, Evi
651:15 February
629:17 December
566:17 December
521:17 December
476:17 December
370:resolv.conf
180:Dynamic DNS
112:DNS records
43:name server
798:Categories
741:|url=
712:2012-02-14
672:2018-02-05
448:RFC 1035,
419:RFC 1034,
408:References
374:resolvconf
297:DNS caches
254:See also:
192:delegation
100:namespaces
66:namespaces
18:DNS server
772:about.com
732:cite book
472:. BCP 219
432:RFC 781,
392:RealNames
285:root zone
170:secondary
132:recursive
78:hostnames
57:request.
781:Archived
764:Archived
366:resolver
324:See also
205:for the
70:Internet
743:value (
166:primary
155:answers
68:of the
739:Check
719:passwd
703:
278:recdns
34:, see
723:group
647:. IBM
382:Linux
362:(NSS)
234:bit.
745:help
721:and
701:ISBN
653:2012
631:2015
624:1034
607:IETF
568:2015
561:2181
544:IETF
523:2015
516:2136
499:IETF
478:2015
470:IETF
378:Unix
376:for
330:BIND
318:nscd
159:zone
76:and
621:RFC
611:doi
558:RFC
548:doi
513:RFC
503:doi
272:or
264:or
139:and
130:or
32:DNS
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730:{{
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226:(
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