Editing Root name server (section)

==Root server addresses==
There are 13 logical root name servers specified, with logical names in the form {{mono|''letter''.root-servers.net}}, where {{mono|''letter''}} ranges from a to m. The choice of thirteen name servers was made because of limitations in the original DNS specification, which specifies a maximum packet size of 512 bytes when using the [[User Datagram Protocol]] (UDP).<ref>RFC 1035 Domain names – implementation and specification</ref> Technically however, fourteen name servers fit into an IPv4 packet. The addition of IPv6 addresses for the root name servers requires more than 512 bytes, which is facilitated by the [[Extension Mechanisms for DNS|EDNS0 extension]] to the DNS standard.<ref>[https://www.icann.org/en/system/files/files/sac-018-en.pdf ICANN: Accommodating IP Version 6 Address Resource Records for the Root of the Domain Name System]</ref>

This does not mean that there are only 13 physical servers; each operator uses redundant computer equipment to provide reliable service even if failure of hardware or software occurs. Additionally, all operate in multiple geographical locations using a routing technique called [[anycast]] addressing, providing increased performance and even more fault tolerance. An informational homepage exists for every logical server (except G-Root) under the [https://root-servers.org/ Root Server Technical Operations Association] domain with web address in the form  {{mono|http://''letter''.root-servers.org/}}, where {{mono|''letter''}} ranges from a to m.

Ten servers were originally in the United States; all are now operated using anycast addressing. Three servers were originally located in Stockholm (I-Root), Amsterdam (K-Root), and Tokyo (M-Root) respectively.
Older servers had their own name before the policy of using similar names was established. With anycast, most of the physical root servers are now outside the United States, allowing for high performance worldwide.

{| class="wikitable sortable" style="font-size:85%;"
|-
! Letter
! [[IPv4]] address
! [[IPv6]] address
! [[Autonomous system (Internet)|AS-number]]<ref name="root_org">AS-numbers and IP-addresses from [https://root-servers.org/ Root-servers.org homepage] checked 9 January 2014</ref>
! Old name
! Operator
! Operator origin
! Location & no. of<br />sites (global/local)<ref>Location and sites from [http://root-servers.org/ Root-servers.org homepage] checked 10 October 2014</ref>
! Software
|-
! [http://a.root-servers.org/ A]
| {{IPaddr|198.41.0.4}}
| {{IPaddr|2001:503:ba3e::2:30}}
| AS19836,<ref name="root_org"/><ref group="note">[https://stat.ripe.net/widget/bgplay#w.resource=AS19836&w.ignoreReannouncements=true&w.rrcs=0,1,6,7,11,14,3,4,5,10,12,13,15&w.starttime=1356998400&w.endtime=1389250800&w.instant=null&w.type=bgp AS19836] is not listed by the RIPEstat tool, though one can see it in   https://stat.ripe.net/AS19836#tabId=at-a-glance</ref> AS36619, AS36620, AS36622, AS36625, AS36631, AS64820<ref group="note">[http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=198.41.0.4&matchtype=L&submit=Query+RISwhois AS64820] is listed as "private use" in RIPE's RISwhois tool</ref><ref name="RISwhois_A">{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=198.41.0.4&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |access-date=23 January 2014}}</ref>
| ns.internic.net
| [[Verisign]]
| {{USA}}
| Distributed using [[anycast]]<br/>14/2
|[[NSD]] and Verisign ATLAS
|-
! [https://b.root-servers.org/ B]
| {{IPaddr|170.247.170.2}}<ref name="iana-list">{{cite web|url=https://www.iana.org/domains/root/servers|title=List of Root Servers}}</ref>{{refn|group=note|Originally it was {{IPaddr|128.9.0.107}}; on 29 January 2004, it was changed to {{IPaddr|192.228.79.201}}.<ref>{{Cite web |title=New IPv4 address for b.root-servers.net |url=https://b.root-servers.org/news/2004/02/02/new-ipv4.html |date=2004-02-02 |access-date=2023-10-23 |website=b.root-servers.org}}</ref> On 24 October 2017, it was changed to {{IPaddr|199.9.14.201}}.<ref name="iana-list"/><ref>{{Cite web |title=B-Root's IPv4 address to be renumbered 2017-10-24 |url=https://b.root-servers.org/news/2017/08/09/new-ipv4.html |date=2017-08-09 |access-date=2023-10-23 |website=b.root-servers.org}}</ref>  On 27 November 2023 it was changed to {{IPaddr|170.247.170.2}}, which is the current address.<ref name="b-change-2023-usc">{{Cite web |title=New addresses for b.root-servers.net |url=https://b.root-servers.org/news/2023/05/16/new-addresses.html |date=2023-05-16 |access-date=2023-10-23 |website=b.root-servers.org}}</ref><ref name="b-change-2023-lacnic">{{Cite web |title=LACNIC asigna recursos de numeración al servidor raíz de USC/ISI |trans-title=LACNIC assigns numbering resources to the USC/ISI root server |url=https://www.lacnic.net/6868/1/lacnic/lacnic-asigna-recursos-de-numeracion-al-servidor-raiz-de-usc_isi |date=2023-05-30 |access-date=2023-10-23 |website=www.lacnic.net |language=es}}</ref>}}
| {{IPaddr|2801:1b8:10::b}}<ref name="iana-list"/>
| AS394353<ref>{{cite web|url=https://root-servers.org/|title=Root Server Technical Operations Assn|date=7 August 2017|publisher=root-servers.org|access-date=7 August 2017}}</ref>
| ns1.isi.edu
| [[University of Southern California|USC]]-[[Information Sciences Institute|ISI]]
| {{USA}}
| Distributed using [[anycast]]<br />6/0
| [[BIND]] and [[Knot DNS]]<ref>{{cite web|url=https://b.root-servers.org/news/2021/02/18/bind-and-knot.html |title=B-Root Software Diversity With Bind and Knot |publisher=[[University of Southern California|USC]]-[[Information Sciences Institute|ISI]] |date=18 February 2021 |access-date=21 February 2021}}</ref>
|-
! [https://c.root-servers.org/ C]
| {{IPaddr|192.33.4.12}}
| {{IPaddr|2001:500:2::c}}
| AS2149<ref name="root_org"/><ref>{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=192.33.4.12&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |date=13 October 2013 |access-date=23 January 2014}}</ref>
| c.psi.net
| [[Cogent Communications]]
| {{USA}}
| Distributed using [[anycast]]<br />10/0
| [[BIND]]
|-
! [http://d.root-servers.org/ D]
| {{IPaddr|199.7.91.13}}<ref group="note">Since 3 January 2013; originally was {{IPaddr|128.8.10.90}}.</ref><ref>{{cite web|url=http://d.root-servers.org/renumber.html|title=D-Root is Changing its IPv4 Address on 3 January 2013|access-date=16 December 2012|archive-url=https://web.archive.org/web/20130310100321/http://d.root-servers.org/renumber.html|archive-date=10 March 2013}}</ref>
| {{IPaddr|2001:500:2d::d}}
| AS10886<ref group="note">Since November 2017; originally was AS27.</ref><ref name="root_org"/><ref>[http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=199.7.91.13&matchtype=L&submit=Query+RISwhois RISwhois], excluding less-specific AS3303 route announcement</ref>
| terp.umd.edu
| [[University of Maryland, College Park|University of Maryland]]
| {{USA}}
| Distributed using [[anycast]]<br />22/127
| [[NSD]]<ref name="d">[http://d.root-servers.org/history.html D-root History page]</ref>
|-
! [https://e.root-servers.org/ E]
| {{IPaddr|192.203.230.10}}
| {{IPaddr|2001:500:a8::e}}
| AS21556<ref name="root_org"/><ref name="RISwhois_E">{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=192.203.230.10&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |access-date=30 October 2017}}</ref>
| ns.nasa.gov
| [[Ames Research Center|NASA Ames Research Center]]
| {{USA}}
| Distributed using [[anycast]]<br />117/137
| [[BIND]] and [[NSD]]
|-
! [https://www.isc.org/f-root/ F]
| {{IPaddr|192.5.5.241}}
| {{IPaddr|2001:500:2f::f}}
| AS3557<ref name="root_org"/><ref name="RISwhois_F">{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=192.5.5.241&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |access-date=23 January 2014}}</ref>
| ns.isc.org
| [[Internet Systems Consortium]]
| {{USA}}
| Distributed using [[anycast]]<br />119/119
| [[BIND]]<ref name="f">{{Cite web |url=https://www.isc.org/community/f-root/ |title=F-root {{!}} Internet Systems Consortium |access-date=9 September 2009 |archive-date=25 March 2013 |archive-url=https://web.archive.org/web/20130325180234/http://www.isc.org/community/f-root}}</ref> and Cloudflare <ref>{{Cite web |title=Delivering Dot |url=https://blog.cloudflare.com/f-root/}}</ref>
|-
! [https://disa.mil/G-Root G]<ref group="note">Formerly [https://web.archive.org/web/20110621074912/http://www.nic.mil/ http://www.nic.mil/ (Internet Archive link)]; unlike all other DNS root servers, G-Root does not implement a homepage under root-servers.org, i.e. [http://g.root-servers.org/ http://g.root-servers.org/]{{dead link|date=April 2018 |bot=InternetArchiveBot |fix-attempted=yes }}.</ref>
| {{IPaddr|192.112.36.4}}<ref group="note" name="noping">Unlike all other DNS root servers, G-Root does not respond to [[Ping (networking utility)|pings]].</ref>
| {{IPaddr|2001:500:12::d0d}}<ref group="note" name="noping" />
| AS5927<ref name="root_org"/><ref>{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=192.112.36.4&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |date=18 September 2013 |access-date=23 January 2014}}</ref>
| ns.nic.ddn.mil
| [[Defense Information Systems Agency]]
| {{USA}}
| Distributed using [[anycast]]<br />6/0
| [[BIND]]
|-
! [https://h.root-servers.org/ H]
| {{IPaddr|198.97.190.53}}<ref group="note">Since 1 December 2015; originally was {{IPaddr|128.63.2.53}}.</ref><ref name="hrootchange" />
| {{IPaddr|2001:500:1::53}}<ref group="note">Since 1 December 2015; originally was {{IPaddr|2001:500:1::803f:235}}.</ref><ref name="hrootchange">{{cite web|publisher=DNSOP|url=https://www.ietf.org/mail-archive/web/dnsop/current/msg15330.html|title=Advance notice – H-root address change on December 1, 2015 | date=31 August 2015 | access-date=19 February 2018}}</ref>
| AS1508<ref name="hrootchange"/><ref group="note">Since 1 December 2015; originally was AS13.</ref><ref>{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=128.63.2.53&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |date=2 January 2014 |access-date=23 January 2014}}</ref>
| aos.arl.army.mil
| [[United States Army Research Laboratory|U.S. Army Research Lab]]
| {{USA}}
| Distributed using [[anycast]]<br />8/0
| [[NSD]]
|-
! [https://web.archive.org/web/20101123140731/http://i.root-servers.org/ I]
| {{IPaddr|192.36.148.17}}
| {{IPaddr|2001:7fe::53}}
| AS29216<ref name="root_org"/><ref>{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=192.36.148.17&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |access-date=23 January 2014}}</ref>
| nic.nordu.net
| [[Netnod Internet Exchange i Sverige|Netnod]]
| {{SWE}}
| Distributed using [[anycast]]<br/>63/2
| [[BIND]]
|-
! [http://j.root-servers.org/ J]
| {{IPaddr|192.58.128.30}}<ref group="note">Since November 2002; originally was {{IPaddr|198.41.0.10}}.</ref>
| {{IPaddr|2001:503:c27::2:30}}
| AS26415,<ref name="root_org"/><ref name="RISwhois_J">{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=192.58.128.30&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |access-date=23 January 2014}}</ref> AS36626, AS36628, AS36632<ref name="RISwhois_J"/>
| {{n/a}}
| [[Verisign]]
| {{USA}}
| Distributed using [[anycast]]<br />63/55
|[[NSD]] and Verisign ATLAS
|-
! [https://www.ripe.net/analyse/dns/k-root/ K]
| {{IPaddr|193.0.14.129}}
| {{IPaddr|2001:7fd::1}}
| AS25152<ref name="root_org"/><ref>{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=193.0.14.129&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |date=20 June 2013 |access-date=23 January 2014}}</ref><ref>{{cite web|url=https://www.peeringdb.com/asn/25152|title=Peering Networks Detailed View|date=21 October 2013|publisher=Peeringdb.com|access-date=23 January 2014}}</ref>
| {{n/a}}
| [[RIPE NCC]]
| {{NED}}
| Distributed using [[anycast]]<br />70/3
| [[BIND]], [[NSD]] and [[Knot DNS]]<ref name="k">[http://k.root-servers.org/ K-root Homepage]</ref>
|-
! [http://l.root-servers.org/ L]
| {{IPaddr|199.7.83.42}}<ref group="note">Since 1 November 2007; originally was {{IPaddr|198.32.64.12}}.</ref><ref>{{cite web|publisher=[[ICANN]]|url=https://www.icann.org/news/blog/advisory-l-root-changing-ip-address-on-1st-november|title=Advisory — "L Root" changing IP address on 1 November}}</ref>
| {{IPaddr|2001:500:9f::42}}<ref group="note">Since 23 March 2016; originally was {{IPaddr|2001:500:3::42}}.</ref><ref>{{cite web|publisher=[[ICANN]]|url=http://www.dns.icann.org/2015/11/05/l-root-ipv6-renumbering/|title=L-Root IPv6 Renumbering|archive-url=https://web.archive.org/web/20160422133507/http://www.dns.icann.org/2015/11/05/l-root-ipv6-renumbering/|archive-date=22 April 2016}}</ref>
| AS20144<ref name="root_org"/><ref>[http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=199.7.83.42&matchtype=L&submit=Query+RISwhois], excluding less-specific AS3303 route announcement</ref><ref>{{cite web|url=https://www.peeringdb.com/asn/20144|title=Peering Networks Detailed View|date=15 April 2013|publisher=Peeringdb.com|access-date=23 January 2014}}</ref>
| {{n/a}}
| [[ICANN]]
| {{USA}}
| Distributed using [[anycast]]<br/>165/0
| [[NSD]] and [[Knot DNS]]<ref name="l">[http://l.root-servers.org/ l.root-servers.net]</ref>
|-
! [https://m.root-servers.org/ M]
| {{IPaddr|202.12.27.33}}
| {{IPaddr|2001:dc3::35}}
| AS7500<ref name="root_org"/><ref>{{cite web|url=http://www.ris.ripe.net/cgi-bin/riswhois.cgi?address=202.12.27.33&matchtype=L&submit=Query+RISwhois |title=RIS – RIPE Network Coordination Centre |publisher=Ris.ripe.net |date=21 October 2013 |access-date=23 January 2014}}</ref><ref>{{cite web|url=https://www.peeringdb.com/asn/7500|title=Peering Networks Detailed View|date=23 December 2013|publisher=Peeringdb.com|access-date=23 January 2014}}</ref>
| {{n/a}}
| [[WIDE Project]]
| {{JAP}}
| Distributed using [[anycast]]<br />4/1
| [[BIND]]
|}
[[File:Root-current.svg|thumb|500px|right|A map of the thirteen logical name servers, including anycasted instances, at the end of 2006]]

There are also several alternative namespace systems with an [[alternative DNS root]] using their own set of root name servers that exist in parallel to the mainstream name servers. The first, [[AlterNIC]], generated a substantial amount of press.{{Citation needed|date=October 2010}}

The function of a root name server may also be implemented locally, or on a provider network. Such servers are synchronized with the official root zone file [https://www.internic.net/zones/root.zone as published] by [[ICANN]], and do not constitute an alternate root.

{{missing information|section|2010 and 2012 China GFW issues with anycast endpoints|date=July 2020}}
As the root name servers are an important part of the Internet, they have come [[DNS Backbone DDoS Attacks|under attack]] several times, although none of the attacks have ever been serious enough to severely affect the performance of the Internet.