- Use multiple servers: Always configure at least 3–4 servers from different providers to avoid single points of failure.
- Mix vendors & geographies: Don’t rely solely on one provider (e.g., all Google or all NIST). Spread across commercial, academic, and public pools.
- Prefer Anycast where possible: For global reach, use pool.ntp.org, time.google.com, ntp.se, etc. These automatically route you to the nearest healthy server.
- Favor stratum 1/2 servers: Stratum 1 servers are closest to the reference clock; stratum 2 are usually fine and often less overloaded.
- Regional selection: Pick servers close to your geography (e.g., europe.pool.ntp.org in Europe, north-america.pool.ntp.org in North America).
- Fallbacks: Include a mix of pool.ntp.org and vendor-specific (Google, Cloudflare, Microsoft) for redundancy.
- Avoid overloading stratum-1 community servers: Unless you have permission, rely on pool.ntp.org for general sync and keep direct stratum-1 queries for critical systems.
- Security tip: Use authenticated NTP (NTS – Network Time Security) where available.
You can quickly validate that an NTP server is reachable and responding using standard tools.
ntpq -p <server>Example:
ntpq -p time.google.comchronyc sources -vAdd a server first:
sudo chronyc add server time.cloudflare.com
sudo chronyc sources -vsudo ntpdate -q pool.ntp.orgThese commands help you confirm:
- Reachability of the server
- Round-trip delay (latency)
- Offset from local clock
- Stratum level reported
- Big Tech Clouds
- Google, AWS, Cloudflare, Facebook/Meta, Microsoft, Apple
- Government / Standards
- NIST, USNO (.mil), PTB (DE), INRIM (IT), ROA (ES), CENAM (MX), VNIIFTRI (RU), NICT (JP), NTSC/CAS (CN), NRC (CA)
- Regional Exchanges / Research Networks
- Netnod (SE), QiX (CA), YYCIX (CA), MSK-IX (RU), RIPE (EU), TimeNL/SIDN (NL), ISC, NTT, HE.net
- Pool.ntp.org zones
- Global, regional, distro/vendor sub-pools
- Trusted Vendors
- Hetzner, Mobatime, Trabia
- Academic / Research one-offs
- Berkeley, GSU, Saskatchewan, NSU, ITAEC, RSU, etc.
- Corporate/Telco/Historical
- DEC/Compaq/HP, others
- Miscellaneous TLD sections
- .edu, .org, .net, .com, country-code lists (.de, .nl, .at, .cz, .pl, .ro, .se, .ca, .mx, .es, .it, .be, .hu, .eus, .ch, .cn, .jp, .br, .cl), .int
- Best Practices for Using NTP
- How to Test NTP Servers
- Organization by Category
- Additional Providers (New)
- Additional Providers (New)
- Google Public NTP [AS15169]: (UTC-aligned, vendor-operated · Anycast · Leap Smear)
- public Amazon Time Sync Service [AS16509, AS14618, AS399991]: (UTC-aligned, vendor-operated · Anycast · Leap Smear)
- Cloudflare NTP [AS13335]: (Supports NTS 🔒 · UTC-aligned, vendor-operated · Anycast · Leap Second UTC step)
- Facebook NTP [AS32934]: (UTC-aligned, vendor-operated)
- Microsoft NTP server [AS8075]: (UTC-aligned, vendor-operated)
- Apple NTP server [AS714, AS6185]: (UTC-aligned, vendor-operated)
- DEC/Compaq/HP: (Legacy · UTC-synced, non-official)
- NIST Internet Time Service (ITS) [AS49, AS104]: (UTC official source · Stratum-1/2 mix · Leap Second UTC step)
- VNIIFTRI: (UTC official source (RU) · Stratum-1/2)
- Mobatime: (Vendor · Stratum-1)
- NTP SERVERS: (Vendor aggregate)
- Stratum1: (Stratum-1)
- time.in.ua: (Regional · Stratum-1/2)
- Company Delfa Co. Ltd. [AS8915]: (Vendor)
- ACO.net [AS1853]: (Academic/Network)
- Berkeley [AS25]: (Academic · UTC-synced, non-official)
- Georgia State University [AS10631]: (Academic · UTC-synced, non-official)
- University of Saskatchewan [AS22950]: (Academic · UTC-synced, non-official)
- NSU [AS3335]: (Academic · UTC-synced, non-official · Stratum-2)
- ITAEC [AS41783]: (Academic/Network)
- RSU [AS47124]: (Academic · Stratum-1)
- National Institute of Information and Communications Technology [AS9355]: (UTC official source (JP) · Stratum-1 · Leap Second UTC step)
- NTT [AS2914]: (Carrier/vendor · UTC-aligned)
- HE.net Public Stratum 1 NTP servers [AS6939]: (Vendor · Stratum-1)
- TRC Fiord [AS28917]: (Vendor)
- Netnod NTP service [AS57021]: (Supports NTS 🔒 · UTC official source (SE/UTC(SP)) · Stratum-1 · Anycast · Leap Second UTC step)
- QiX NTP [AS14086]: (IXP · Regional)
- YYCIX NTP [AS396515]: (IXP · Regional)
- MSK-IX NTP [AS43832]: (IXP · Stratum-1)
- Hetzner Online [AS24940]: (Vendor)
- Trabia-Network [AS43289]: (Vendor)
- RIPE [AS3333]: (Vendor/Community)
- Internet Systems Consortium [AS1280]: (Vendor/Community)
- TimeNL/SIDN Labs [AS1140]: (Supports NTS 🔒 · UTC official source (NL/UTC(NL)) · Stratum-1 · Leap Second UTC step)
- Kantonsschule Zug [AS34288]: (Academic)
- INTERNET MULTIFEED CO. [AS7521]: (Carrier/vendor)
- Chinese Academy of Sciences Nation Time Service Center [AS4808, AS9808, AS23724]: (UTC official source (CN) · Stratum-1 · Leap Second UTC step)
- Nat Morris [AS30746]: (Individual · Stratum-1)
- NTP Pool: (Anycast · Geo-distributed)
- .mil: (UTC official source – USNO)
- .edu: (Academic · UTC-synced, non-official)
- .com: (Mixed vendor)
- .net: (Mixed vendor)
- .org: (Community/Nonprofit)
- .de: (Includes PTB · UTC official source (DE))
- .nl: (Includes VSL/Time labs)
- .at: (Austria)
- .cz: (Czechia)
- .pl: (Poland · includes GUM)
- .ro: (Romania)
- .se: (Sweden)
- .ca: (Includes NRC · UTC official source (CA))
- .mx: (Includes CENAM · UTC official source (MX))
- .es: (Includes ROA · UTC official source (ES))
- .it: (Includes INRIM · UTC official source (IT))
- .be: (Belgium)
- .hu: (Hungary)
- .eus: (Basque Country)
- .ch: (Switzerland)
- .cn: (China)
- .jp: (Japan · includes NICT official source)
- .br: (Brazil)
- .cl: (Chile)
- .int: (International orgs · includes ESA)
- Resources
Commonly referenced endpoints not present in the original dump. Availability can vary by ASN/region — test first.
- OVH — ntp.ovh.net
- Linode / Akamai — time.linode.com
- Level 3 / CenturyLink — ntp.level3.com
NTS (Network Time Security): Cloudflare supports NTS on
time.cloudflare.com:4460. Some national/regional services (e.g., Netnod, TimeNL) also support NTS — see their docs and test in your environment.
time.google.com
time1.google.com
time2.google.com
time3.google.com
time4.google.com
time.android.com
public Amazon Time Sync Service [AS16509, AS14618, AS399991]: (UTC-aligned, vendor-operated · Anycast · Leap Smear)
time.aws.com
amazon.pool.ntp.org
0.amazon.pool.ntp.org
1.amazon.pool.ntp.org
2.amazon.pool.ntp.org
3.amazon.pool.ntp.org
Cloudflare NTP [AS13335]: (Supports NTS 🔒 · UTC-aligned, vendor-operated · Anycast · Leap Second UTC step)
time.cloudflare.com
time.facebook.com
time1.facebook.com
time2.facebook.com
time3.facebook.com
time4.facebook.com
time5.facebook.com
time.windows.com
time.apple.com
time-macos.apple.com
time-ios.apple.com
time1.apple.com
time2.apple.com
time3.apple.com
time4.apple.com
time5.apple.com
time6.apple.com
time7.apple.com
time.euro.apple.com
clepsydra.dec.com/clepsydra.labs.hp.com/clepsydra.hpl.hp.com/usno.labs.hp.com
NIST Internet Time Service (ITS) [AS49, AS104]: (UTC official source · Stratum-1/2 mix · Leap Second UTC step)
time-a-g.nist.gov
time-b-g.nist.gov
time-c-g.nist.gov
time-d-g.nist.gov
time-a-wwv.nist.gov
time-b-wwv.nist.gov
time-c-wwv.nist.gov
time-d-wwv.nist.gov
time-a-b.nist.gov
time-b-b.nist.gov
time-c-b.nist.gov
time-d-b.nist.gov
time.nist.gov
time-e-b.nist.gov
time-e-g.nist.gov
time-e-wwv.nist.gov
time-nw.nist.gov
time-a.nist.gov
time-b.nist.gov
utcnist.colorado.edu
utcnist2.colorado.edu
ntp1.vniiftri.ru
ntp2.vniiftri.ru
ntp3.vniiftri.ru
ntp4.vniiftri.ru
ntp.sstf.nsk.ru
ntp1.niiftri.irkutsk.ru
ntp2.niiftri.irkutsk.ru
vniiftri.khv.ru
vniiftri2.khv.ru
ntp21.vniiftri.ru
ntp.mobatime.ru
ntp0.ntp-servers.net
ntp1.ntp-servers.net
ntp2.ntp-servers.net
ntp3.ntp-servers.net
ntp4.ntp-servers.net
ntp5.ntp-servers.net
ntp6.ntp-servers.net
ntp7.ntp-servers.net
ntp1.stratum1.ru
ntp2.stratum1.ru
ntp3.stratum1.ru
ntp4.stratum1.ru
ntp5.stratum1.ru
ntp1.stratum2.ru Москва
ntp2.stratum2.ru
ntp3.stratum2.ru
ntp4.stratum2.ru
ntp5.stratum2.ru
stratum1.net
ntp.time.in.ua
ntp2.time.in.ua
ntp3.time.in.ua
ntp.ru
ts1.aco.net
ts2.aco.net
ntp1.net.berkeley.edu
ntp2.net.berkeley.edu
ntp.gsu.edu
tick.usask.ca
tock.usask.ca
ntp.nsu.ru
ntp.psn.ru
ntp.rsu.edu.ru
National Institute of Information and Communications Technology [AS9355]: (UTC official source (JP) · Stratum-1 · Leap Second UTC step)
ntp.nict.jp
x.ns.gin.ntt.net
y.ns.gin.ntt.net
clock.sjc.he.net
clock.fmt.he.net
clock.nyc.he.net
ntp.fiord.ru
Netnod NTP service [AS57021]: (Supports NTS 🔒 · UTC official source (SE/UTC(SP)) · Stratum-1 · Anycast · Leap Second UTC step)
Göteborg:
gbg1.ntp.se
gbg2.ntp.se
Malmö:
mmo1.ntp.se
mmo2.ntp.se
Stockholm:
sth1.ntp.se
sth2.ntp.se
Sundsvall:
svl1.ntp.se
svl2.ntp.se
Anycast address for nearest NTP server of the above:
ntp.se
ntp.qix.ca
ntp1.qix.ca
ntp2.qix.ca
ntp.yycix.ca
ntp.ix.ru
ntp1.hetzner.de
ntp2.hetzner.de
ntp3.hetzner.de
time-a.as43289.net
time-b.as43289.net
time-c.as43289.net
ntp.ripe.net
clock.isc.org (prev ntp.isc.org)
TimeNL/SIDN Labs [AS1140]: (Supports NTS 🔒 · UTC official source (NL/UTC(NL)) · Stratum-1 · Leap Second UTC step)
ntp.time.nl (ntp1.time.nl)
ntp0.as34288.net
ntp1.as34288.net
ntp1.jst.mfeed.ad.jp
ntp2.jst.mfeed.ad.jp
ntp3.jst.mfeed.ad.jp
Chinese Academy of Sciences Nation Time Service Center [AS4808, AS9808, AS23724]: (UTC official source (CN) · Stratum-1 · Leap Second UTC step)
ntp.ntsc.ac.cn
ntp.nat.ms
pool.ntp.org
0.pool.ntp.org
1.pool.ntp.org
2.pool.ntp.org
3.pool.ntp.org
europe.pool.ntp.org
0.europe.pool.ntp.org
1.europe.pool.ntp.org
2.europe.pool.ntp.org
3.europe.pool.ntp.org
asia.pool.ntp.org
0.asia.pool.ntp.org
1.asia.pool.ntp.org
2.asia.pool.ntp.org
3.asia.pool.ntp.org
ru.pool.ntp.org
0.ru.pool.ntp.org
1.ru.pool.ntp.org
2.ru.pool.ntp.org
3.ru.pool.ntp.org
north-america.pool.ntp.org
0.north-america.pool.ntp.org
1.north-america.pool.ntp.org
2.north-america.pool.ntp.org
3.north-america.pool.ntp.org
0.gentoo.pool.ntp.org
1.gentoo.pool.ntp.org
2.gentoo.pool.ntp.org
3.gentoo.pool.ntp.org
0.arch.pool.ntp.org
1.arch.pool.ntp.org
2.arch.pool.ntp.org
3.arch.pool.ntp.org
0.fedora.pool.ntp.org
1.fedora.pool.ntp.org
2.fedora.pool.ntp.org
3.fedora.pool.ntp.org
0.opensuse.pool.ntp.org
1.opensuse.pool.ntp.org
2.opensuse.pool.ntp.org
3.opensuse.pool.ntp.org
0.centos.pool.ntp.org
1.centos.pool.ntp.org
2.centos.pool.ntp.org
3.centos.pool.ntp.org
0.debian.pool.ntp.org
1.debian.pool.ntp.org
2.debian.pool.ntp.org
3.debian.pool.ntp.org
0.askozia.pool.ntp.org
1.askozia.pool.ntp.org
2.askozia.pool.ntp.org
3.askozia.pool.ntp.org
0.freebsd.pool.ntp.org
1.freebsd.pool.ntp.org
2.freebsd.pool.ntp.org
3.freebsd.pool.ntp.org
0.netbsd.pool.ntp.org
1.netbsd.pool.ntp.org
2.netbsd.pool.ntp.org
3.netbsd.pool.ntp.org
0.openbsd.pool.ntp.org
1.openbsd.pool.ntp.org
2.openbsd.pool.ntp.org
3.openbsd.pool.ntp.org
0.dragonfly.pool.ntp.org
1.dragonfly.pool.ntp.org
2.dragonfly.pool.ntp.org
3.dragonfly.pool.ntp.org
0.pfsense.pool.ntp.org
1.pfsense.pool.ntp.org
2.pfsense.pool.ntp.org
3.pfsense.pool.ntp.org
0.opnsense.pool.ntp.org
1.opnsense.pool.ntp.org
2.opnsense.pool.ntp.org
3.opnsense.pool.ntp.org
0.smartos.pool.ntp.org
1.smartos.pool.ntp.org
2.smartos.pool.ntp.org
3.smartos.pool.ntp.org
0.android.pool.ntp.org
1.android.pool.ntp.org
2.android.pool.ntp.org
3.android.pool.ntp.org
0.amazon.pool.ntp.org
1.amazon.pool.ntp.org
2.amazon.pool.ntp.org
3.amazon.pool.ntp.org
0.ubnt.pool.ntp.org
1.ubnt.pool.ntp.org
2.ubnt.pool.ntp.org
3.ubnt.pool.ntp.org
tick.usno.navy.mil
tock.usno.navy.mil
ntp2.usno.navy.mil
utcnist.colorado.edu
utcnist2.colorado.edu
timekeeper.isi.edu
rackety.udel.edu
mizbeaver.udel.edu
otc1.psu.edu
gnomon.cc.columbia.edu
navobs1.gatech.edu
navobs1.wustl.edu
now.okstate.edu
ntp.colby.edu
ntp-s1.cise.ufl.edu
bonehed.lcs.mit.edu
level1e.cs.unc.edu
tick.ucla.edu
tick.uh.edu
ntpstm.netbone-digital.com
nist1.symmetricom.com
ntp.quintex.com
ntp1.conectiv.com
tock.usshc.com
t2.timegps.net
gps.layer42.net
ntp-ca.stygium.net
sesku.planeacion.net
ntp0.nl.uu.net
ntp1.nl.uu.net
navobs1.oar.net
ntp-galway.hea.net
ntp1.ona.org
ntp.your.org
ntp.mrow.org
time.fu-berlin.de
ntps1-0.cs.tu-berlin.de
ntps1-1.cs.tu-berlin.de
ntps1-0.uni-erlangen.de
ntps1-1.uni-erlangen.de
ntp1.fau.de
ntp2.fau.de
ntp.dianacht.de
zeit.fu-berlin.de
ptbtime1.ptb.de
ptbtime2.ptb.de
rustime01.rus.uni-stuttgart.de
rustime02.rus.uni-stuttgart.de
chime1.surfnet.nl
ntp.vsl.nl
asynchronos.iiss.at
ntp.nic.cz
time.ufe.cz
ntp.fizyka.umk.pl
tempus1.gum.gov.pl
tempus2.gum.gov.pl
ntp1.usv.ro
ntp3.usv.ro
timehost.lysator.liu.se
time1.stupi.se
time.nrc.ca
clock.uregina.ca
cronos.cenam.mx
ntp.lcf.mx
hora.roa.es
minuto.roa.es
ntp1.inrim.it
ntp2.inrim.it
ntp1.oma.be
ntp2.oma.be
ntp.atomki.mta.hu
ntp.i2t.ehu.eus
ntp.neel.ch
ntp.neu.edu.cn
ntp.nict.jp
ntps1.pads.ufrj.br
ntp.shoa.cl
time.esa.int
time1.esa.int
http://support.ntp.org/bin/view/Servers/StratumOneTimeServers
http://support.ntp.org/bin/view/Servers/StratumTwoTimeServers
http://support.ntp.org/bin/view/Servers/NTPPoolServers
http://www.pool.ntp.org/zone/@
http://www.pool.ntp.org/zone/asia
http://www.pool.ntp.org/zone/europe
http://www.pool.ntp.org/zone/north-america
http://www.pool.ntp.org/zone/oceania
http://www.pool.ntp.org/zone/south-america
https://www.ntp-server.de/ntp-server-deutschland/
https://www.ntp-server.de/ntp-server-oesterreich/
https://www.ntp-server.de/ntp-server-schweiz/
https://www.he.net/adm/ntp.html
validate data here
- http://support.ntp.org/bin/view/Servers/StratumOneTimeServers
- http://support.ntp.org/bin/view/Servers/StratumTwoTimeServers
- http://support.ntp.org/bin/view/Servers/NTPPoolServers
- http://www.pool.ntp.org/zone/@
- http://www.pool.ntp.org/zone/asia
- http://www.pool.ntp.org/zone/europe
- http://www.pool.ntp.org/zone/north-america
- http://www.pool.ntp.org/zone/oceania
- http://www.pool.ntp.org/zone/south-america
- https://time.nl/
- https://time.nl/index_en.html
- http://time.in.ua/
- https://www.chrony.eu/status
- https://www.ntp-server.de/ntp-server-deutschland/
- https://www.ntp-server.de/ntp-server-oesterreich/
- https://www.ntp-server.de/ntp-server-schweiz/
- https://www.he.net/adm/ntp.html