There are two levels, or tiers, of Network Time Protocol
(NTP) time servers that are available on the Internet. The NTP is defined in
Request for Comments (RFC) 1305.
The first-level time servers are
primarily intended to act as source time servers for second-level time servers.
The first-level time servers may also be capable of providing mission-critical
time services. Some first-level time servers may have a restricted access
policy.
Second-level time servers are intended for general SNTP time
service needs. Second-level time servers usually enable public access. It is
recommended that you use second-level time servers for normal SNTP time server
configuration because they are usually located on a closer network that can
produce faster updates.
It is recommended that you research any time
server selection to ensure that it can meet your specific time server
requirements.
The National Institute of Standards and Technology
(NIST) maintains a network of time servers that provide time and frequency
services for the United States. More information about the NIST may be found at
the following Web sites:
The US Naval Observatory also maintains a network of time servers
available for public access. To see a list of servers and their descriptions,
visit the following US Naval Observatory Web site:
The NTP uses port 123 so this port must be opened on a firewall
or router to ensure proper communication with the NTP
server.
For more information about the use of time services in Windows Server and Windows
NT, click the following article numbers to view the articles in the Microsoft Knowledge Base:
243574
(http://support.microsoft.com/kb/243574/
)
"Could not locate a time server" after setting SNTP time server using NET TIME command
216734
(http://support.microsoft.com/kb/216734/
)
How to configure an authoritative time server in Windows 2000
224799
(http://support.microsoft.com/kb/224799/
)
Basic operation of the Windows Time Service
The following list of NTP time servers is provided as a reference
only. This list is not intended to be comprehensive. This list describes
currently active NTP time servers that may or may not be able to accommodate
your time service needs.
Any NTP time server selection should be
evaluated to determine if the server in question meets your specific time
server requirements.
Palo Alto, CA: Systems Research Center, Compaq Computer
Corp. 204.123.2.72: usno.pa-x.dec.com; CNAME: navobs1.pa-x.dec.com
Service area: U.S. pacific and mountain time zones
Marina del Rey, CA: USC Information Sciences Institute
128.9.176.30: timekeeper.isi.edu Service Area: CalRen2 and Los Nettos
region
Washington, DC: U.S. Naval Observatory 192.5.41.41:
tock.usno.navy.mil 192.5.41.40: tick.usno.navy.mil Service Area:
NSFNET
Ottawa, Ontario, Canada: National Research Council of
Canada time.chu.nrc.ca Service Area: Canada
Raleigh, NC: North Carolina State University
152.1.58.124: terrapin.csc.ncsu.edu Service Area: Southeastern
U.S.
Cambridge, MA: MIT Information Systems 18.72.0.3:
bitsy.mit.edu Service Area: NSFNET and NEARnet area
Cambridge, MA: MIT 18.26.4.105:
bonehed.lcs.mit.edu Service Area: Eastern U.S.
Palo Alto, CA: Internet Software Consortium
192.5.5.250: clock.isc.org Service Area: BARRnet, Alternet-west, and
CIX-west
Cambridge, MA: Open Software Foundation 130.105.4.59:
clock.osf.org Service Area: NSFNET and NEARnet region
Cleveland, OH: Lewis Research Center (NASA)
128.156.1.43: lerc-dns.lerc.nasa.gov Service Area: NSFNET and
OARNET
Colorado Springs, CO: Schriever AFB 204.34.198.40:
navobs1.usnogps.navy.mil; CNAME: tick.usnogps.navy.mil 204.34.198.41:
navobs2.usnogps.navy.mil; CNAME: tock.usnogps.navy.mil Service area: U.S.
pacific and mountain time zones
St. Louis, MO: Washington University 128.252.19.1:
navobs1.wustl.edu; CNAME: tick.wustl.edu Service area: U.S. central time
zone
Research Triangle Park, NC: MCNC 192.101.21.1:
ncnoc.ncren.net Service area: NC-REN region
Cupertino, CA: HP 192.6.38.127:
ntp-cup.external.hp.com Service Area: West coast U.S.
Newark, DE: Conectiv Communications 138.39.7.20:
ntp1.delmarva.com Service area: Cable & Wireless Network (formerly
MCInet)
University Park, PA: Penn State University
128.118.46.3: otc1.psu.edu Service Area: NSFNET, PREPNET, and JvNCnet
Europe
Borowiec, Poland: Astrogeodynamical Observatory, Space
Research Centre 150.254.183.15: vega.cbk.poznan.pl Service Area:
Poland and Europe
Stockholm, Sweden: Stupi AB 192.36.143.151:
Time2.Stupi.SE Service Area: Europe
Torino, Italy: IEN Galileo Ferraris 193.204.114.1:
time.ien.it Service Area: Italy and Europe
Zurich, Switzerland: Integrated Systems Lab, Swiss Fed.
Inst. of Technology 129.132.2.21: swisstime.ethz.ch Service Area:
Switzerland and Europe
Torino, Italy: CSTV of National Research Council
150.145.33.1: tempo.cstv.to.cnr.it Service Area: Italy and
Europe
Erlangen, Germany: University Erlangen-Nuernberg
ntp0.fau.de; ntp1.fau.de; ntp2.fau.de; ntps1-0.uni-erlangen.de;
ntps1-1.uni-erlangen.de; ntps1-2.uni-erlangen.de Service Area: Germany and
Europe
Berlin, Germany: Technische Universitaet Berlin
130.149.17.21: ntps1-0.cs.tu-berlin.de 130.149.17.8:
ntps1-1.cs.tu-berlin.de Service Area: Germany and Europe
Germany 131.173.17.7:
ntps1-1.rz.Uni-Osnabrueck.DE Service Area: Germany and Europe
Sweden 192.36.143.150: Time1.Stupi.SE Service
Area: SUnet and NORDUnet Sweden
East Asia and Pacific Rim
Hong Kong: The Chinese University of Hong Kong.
137.189.6.18: clock.cuhk.edu.hk Service Area: Hong Kong, China, and South
East Asia
Fukuoka, Japan: Fukuoka University 133.100.9.2:
clock.nc.fukuoka-u.ac.jp 133.100.11.8: clock.tl.fukuoka-u.ac.jp
Service Area: Japan and Pacific area
Australia
Melbourne Australia: The University of Melbourne
128.250.36.2: ntp.cs.mu.OZ.AU Service area: Australia and New Zealand
Quebec, Canada: Canadian Meteorological Center
ntp1.cmc.ec.gc.ca; ntp2.cmc.ec.gc.ca Service Area: Eastern Canada
Ontario, Canada: National Research Council of Canada
time.chu.nrc.ca; time.nrc.ca Service Area: Canada
Saskatchewan, Canada: University of Regina
142.3.100.15: timelord.uregina.ca Service Area: Canada
Ontario, Canada: University of Toronto
tick.utoronto.ca; tock.utoronto.ca Service Area: Eastern Canada
Mexico: Audiotel office ntp2a.audiotel.com.mx;
ntp2c.audiotel.com.mx; ntp2b.audiotel.com.mx Service Area: Avantel,
MCINet, and Mexico
Santa Cruz, CA: Scruz-net, inc. 165.227.1.1:
ns.scruz.net Service area: Western U.S.
San Diego, CA: UCSD Academic Computing Services/Network
Operations 132.239.254.49: ntp.ucsd.edu Service Area: CERFNET;
NSFNET, SDSC region, and nearby
Quincy, California ntp1.mainecoon.com;
ntp2.mainecoon.com Service Area: North America
Newark, DE: University of Delaware 128.175.1.3:
louie.udel.edu Service Area: CAIRN, Abilene, and vBNS
Atlanta, GA: CNSG ntp.shorty.com Service Area:
Southeast U.S.
Kennesaw, GA: PeachNet rolex.peachnet.edu;
timex.peachnet.edu Service Area: PeachNet (Georgia) and Southeast U.S.
Urbana-Champaign, IL: University of Illinois
ntp-0.cso.uiuc.edu; ntp-1.cso.uiuc.edu; ntp-2.cso.uiuc.edu Service Area:
CICNET, Midwest, and NCSA region
Chicago, IL: Argonne National Laboratory
ntp-1.mcs.anl.gov; ntp-2.mcs.anl.gov Service Area: NSF/ANSNet, CICNet,
NetIllinois, and ESNet
West Lafayette, IN: Purdue University
gilbreth.ecn.purdue.edu; harbor.ecn.purdue.edu; molecule.ecn.purdue.edu
Service area: NSFNET and CICNET area
Manhattan, KS: KansasNet OnLine Services
199.240.130.1: ntp1.kansas.net 199.240.130.12: ntp2.kansas.net
Service area: Central U.S. and Great Plains
Boston, MA: UMass-Boston CS dept. 158.121.104.4:
timeserver.cs.umb.edu Service Area: New England
Minneapolis/St Paul, MN: University of Minnesota
ns.nts.umn.edu; nss.nts.umn.edu Service Area: CICNET region
Columbia, MO: University of Missouri-Columbia
128.206.206.12: everest.cclabs.missouri.edu Service Area: MOREnet
Omaha, NE: Radiks Internet Access 205.138.126.83:
allison.radiks.net Service Area: Midwest U.S.
Las Vegas, NV: University of Nevada System Computing
Services 131.216.1.101: cuckoo.nevada.edu Service Area: NevadaNet,
NSFNET, and SDSC region
Las Vegas, NV: UNLV College of Engineering
tick.cs.unlv.edu; tock.cs.unlv.edu Service Area: Sprintnet
New York City, NY: Columbia University
ntp.ctr.columbia.edu Service Area: Sprintlink and NYSERnet
Ithaca, NY: Cornell University 192.35.82.50:
ntp0.cornell.edu Service Area: NSFNET and NYSER region
New York, NY: Morningside Campus, Columbia University
sundial.columbia.edu Service Area: NYSERnet
New York City, NY: Columbia University Computer Science
Department timex.cs.columbia.edu Service Area: PSINET; NSFNET, and
NYSER region
Norman, Oklahoma: University of Oklahoma 129.15.22.8:
constellation.ecn.uoknor.edu Service Area: Midnet
Coos Bay, OR: Koala Computers 207.48.109.6:
tick.koalas.com Service Area: Northwestern U.S.
University Park, PA: Penn State University
128.118.25.3: clock.psu.edu Service Area: Internet2, vBNS,
CERFnet(AT&T IP Services), PSC/NCNE, and CASC
Pittsburgh, PA: Pittsburgh Supercomputing Center
128.182.58.100: fuzz.psc.edu Service area: NSFNET and PSC region
Pittsburgh, PA: Carnegie Mellon Electrical and Computer
Engineering ntp-1.ece.cmu.edu; ntp-2.ece.cmu.edu Service Area:
PREPNET and PSC region
Dallas, TX: Cox School of Business, Southern Methodist
University 129.119.80.126: ntp.cox.smu.edu Service Area: NSFNET and
SESQUI region
Hughes Springs, TX: First National Bank 209.144.20.76:
ntp.fnbhs.com Service area: Northeast Texas
Houston, Tx: Baylor College of Medicine 128.249.1.10:
ntp.tmc.edu Service Area: NSFNET and SESQUI region
College Station, TX: Texas A&M University
165.91.52.110: ntp5.tamu.edu Service area: NSFNET, SESQUI region, THEnet,
and TAMUSDSN
Plano, TX: Greyware Automation Products
tick.greyware.com; tock.greyware.com Service Area: South-Central U.S.
Blacksburg, VA: Virginia Tech Computing Center
ntp-1.vt.edu; ntp-2.vt.edu Service Area: Southeast U.S.
Arlington, VA: Center for Seismic Studies 140.162.1.3:
ntp.cmr.gov Service Area: NSFNET and SURA region
Richland, WA: Washington State University
192.31.216.30: clock.tricity.wsu.edu Service Area: NSFNET and NorthWestNet
Washington, U.S.: Mill Creek time.ultimeth.net
Service Area: Northwest U.S.
Wisconsin, U.S.: Computer Science Department, University of
Wisconsin-Madison ntp1.cs.wisc.edu; ntp2.cs.wisc.edu;
ntp3.cs.wisc.edu Service Area: U.S. and any
South America
Buenos Aires, Argentina: Network Access Point
200.49.40.1: CNAME: tick.nap.com.ar 200.49.32.1: CNAME:
tock.nap.com.ar Service Area: Argentina
Buenos Aires, Argentina: Sinectis S.A.
time.sinectis.com.ar Service Area: Argentina
Brazil: Brazilian Research Network 200.144.121.33:
ntp.cais.rnp.br Service Area: Brazil
Venezuela: VELUG, Grupo de Usuarios Linux de Venezuela
150.185.192.250: ntp.linux.org.ve Service Area: Arica
Europe
Zurich, Switzerland: Swiss Fed. Inst. of Technology
129.132.98.11: bernina.ethz.ch Service Area: Switzerland and Europe
Location: Copenhagen, Denmark, Europe
clock.netcetera.dk; clock2.netcetera.dk Service area: Denmark,
Scandinavia, and Northern Europe
Spain: Altea slug.ctv.es Service Area: Spain
Pieksamaki, Finland: Keski-Savon Oppimiskeskus
tick.keso.fi; tock.keso.fi Service area: Finland
Meudon, France: Observatoire de Paris-Meudon
ntp.obspm.fr Service Area: France and Europe
Lyon, France: CISM ntp.univ-lyon1.fr Service
Area: France, Switzerland, Italy, and Europe
Paris, France: VIA, Ecole Centrale 138.195.130.70:
ntp.via.ecp.fr Service Area: France and Europe
Budapest, Hungary: KFKI Research Institute for Particle and
Nuclear Physics 148.6.0.1: time.kfki.hu Service Area: HUNGARNET
Italy: Net4u Srl, Vercelli, Italy 195.32.52.129:
ntps.net4u.it Service area: Italy
Oslo, Norway: University of Oslo 129.240.64.3:
fartein.ifi.uio.no Service Area: NORDUnet
Oslo, Norway: Alcanet International
time.alcanet.no Service Area: Europe
Krakow, Poland: Academic Computer Centre
149.156.4.11: info.cyf-kr.edu.pl Service Area: Poland and Europe
Lund, Sweden: Lund Institute of Technology
130.235.20.3: ntp.lth.se Service Area: Sweden and NORDUnet
Ljubljana, Slovenia: Institute of Biophysics, University of
Ljubljana biofiz.mf.uni-lj.si 193.2.69.11 Service Area: Slovenia and
Europe
Ljubljana, Slovenia: Hydrometeorological Institute of
Slovenia hmljhp.rzs-hm.si Service Area: Slovenia and Europe
Ljubljana, Slovenia: Academic and Research Network of
Slovenia ntp1.arnes.si; ntp2.arnes.si Service Area: Slovenia and
Europe
Ljubljana, Slovenia: J. Stefan Institute
time.ijs.si Service Area: Slovenia and Europe
British Isles
Dublin, Ireland: School of Mathematics, Trinity College
ntp.cs.tcd.ie; ntp.maths.tcd.ie; ntp.tcd.ie Service Area: Ireland
and U.K.
Glasgow, Scotland: Strathclyde University
ntp.cs.strath.ac.uk Service Area: U.K., Europe, and any
Cambridge, U.K. ntp0.uk.uu.net; ntp1.uk.uu.net;
ntp2.uk.uu.net Service Area: UUNET (formerly known in the U.K. as PIPEX)
and U.K.
Manchester, England: University of Manchester
ntp2a.mcc.ac.uk; ntp2b.mcc.ac.uk; ntp2c.mcc.ac.uk; ntp2d.mcc.ac.uk
Service Area: U.K.
Buckinghamshire U.K.: Wibble U.K., Aylesbury
tick.tanac.net Service area: U.K.
Asia
Moscow, Russia: Landau Institute for Theoretical
Physics 193.233.9.7: ntp.landau.ac.ru Service area: Russia
Russia: Pushchino (near Moscow) 194.149.67.130:
ntp.psn.ru Service area: Russia
Chernogolovka, Russia: Chernogolovka Scientific Center
(near Moscow) 193.233.46.10: sign.chg.ru Service Area: Russia
East Asia and Pacific Rim
Tokyo, Japan: Cyber Fleet, Inc. 203.139.30.195:
ntp.cyber-fleet.net Service Area: Japan and East Asia
Seoul, Korea: Inet, Inc. time.nuri.net Service
Area: Korea, Japan, Hong Kong, and East Asia
Hamilton, New Zealand: The University of Waikato
truechimer.waikato.ac.nz; truechimer1.waikato.ac.nz;
truechimer2.waikato.ac.nz; truechimer3.waikato.ac.nz Service Area: New
Zealand
Singapore and the Philippines: ntp.shim.org
Service Area: Singapore
Africa
Lagos, Nigeria: Supernet300 ntp.supernet300.com
Service Area: Western Africa (primarily Nigerian NITEL backbone)
Pietermaritzburg, South Africa: Natal University
143.128.82.200: ntp.cs.unp.ac.za Service area: South Africa
Australia
Adelaide, South Australia: The University of Adelaide
129.127.28.4: augean.eleceng.adelaide.edu.au 129.127.40.3:
ntp.adelaide.edu.au 203.21.37.18: ntp.saard.net Service area: AARNet
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