 |
| Free Public NTP Servers |
The passage of time has always been fascinating and measuring that passage accurately is important and intellectually simulating to me. Twice every year, during daylight savings time change, I go around the house setting every non-atomic clock to exactly the 00th second of the next minute the best I can, manually referencing a technological marvel on my wrist, a Casio Pathfinder Triple-Sensor Solar that, among numerous awesome things, synchronizes to NIST's WWVB atomic clock signal from Fort Collins, Colorado every night. I have had multiple discussions with the family about running all the clocks in the house in UTC, and actually have a fully functional binary wall-clock and a binary wrist-watch as well.
I run multiple free public Network Time Protocol (NTP) servers that help in distributing time across the world to numerous computer systems and devices. All of my internet-facing NTP servers participate in the NTP Pool Project, and the servers that serve stratum 2 time are also listed at ntp.org.
I have spent significant time locating, testing and short-listing public stratum-1 NTP servers to run my stratum-2 servers off. The remaining servers are stratum-3, with my stratum-2 servers used as time sources among others for them.
The intent of this post is to document all of my ntp.conf NTP daemon configuration files for quick recovery from any catastrophic failure and subsequent reinstallation of any of my servers.
sanyalnet-cloud-vps.freeddns.org
sanyalnet-cloud-vps.freeddns.org is a free public stratum-2 NTP server running on a CentOS 7 virtual machine in a data-center in Kitchener in Ontario, Canada, using the following /etc/ntp.conf NTP configuration file and using free public stratum-1 NTP servers as time sources.
For security, NTP queries are limited to be responsive if issued from localhost only:# ntpq -p 127.0.0.1The easiest way to make sure the server is serving time is to execute a ntpdate query from an external system over the internet:
# ntpdc -p 127.0.0.1
# ntpdate -q 64.137.248.161 #Command Issued on Remote Server
server 64.137.248.161, stratum 2, offset -1.336721, delay 0.05603
27 Mar 02:36:15 ntpdate[22115]: step time server 64.137.248.161 offset -1.336721 sec
# ntpdate -q 64.137.248.212 #Command Issued on Remote Server
server 64.137.248.212, stratum 2, offset -1.374973, delay 0.05621
27 Mar 02:37:10 ntpdate[22121]: step time server 64.137.248.212 offset -1.374973 sec
To monitor the computers this NTP server is serving time to, I use tshark on the corresponding network interface filtered by the two IP addresses of this server:
# nice -n 19 ionice -c3 tshark -i ens33 -Y ntp | egrep "64.137.248.161 ->|64.137.248.212 ->" | grep "server"
Similarly, to monitor the time sources this NTP server is synchronizing time from using tshark:
I have previously described how to install your own OpenVMS VAX server using the SIMH simulator in this post.
Here is my SYS$SPECIFIC:[TCPIP$NTP]TCPIP$NTP.CONF - the NTP configuration file on OpenVMS 7.3 VAX:
# nice -n 19 ionice -c3 tshark -i ens33 -Y ntp | grep "client"
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| # -- | |
| # SANYALnet Labs | |
| # http://tuklusan.decsystem.org/ | |
| # | |
| # This is Supratim Sanyal's NTP Server configuration file | |
| # To test, use "ntpdate -q <this host>" from another host | |
| # This server will not respond to peer queries ("ntpdc -q") etc. from | |
| # external hosts. | |
| # | |
| # The stratum 1 servers used by this server are mostly educational and | |
| # military servers from: | |
| # http://support.ntp.org/bin/view/Servers/StratumOneTimeServers?redirectedfrom=Servers.StratumOne | |
| # Comment out the stratum 2 servers to make this server stratum 2 with | |
| # only stratum 1 peers. All configured peer servers in this file need to | |
| # be stratum 1 servers for this server to be stratum 2. | |
| # Do not use burst, but iburst is ok with most stratum 1 servers. | |
| # | |
| # Supratim Sanyal, supratim at riseup dot net | |
| # ++ | |
| driftfile /var/lib/ntp/ntp.drift | |
| restrict default nomodify notrap nopeer noquery kod limited | |
| restrict 127.0.0.1 | |
| restrict ::1 | |
| # --------------- | |
| # Stratum 1 Peers | |
| # --------------- | |
| # --------------- | |
| # Stratum 1 Peers in Canada, preferred | |
| # --------------- | |
| server ntp.zaf.ca iburst prefer | |
| server ntp1.acorn-ns.ca iburst prefer | |
| server ntp1.torix.ca iburst prefer | |
| server ntp2.acorn-ns.ca iburst prefer | |
| server ntp2.torix.ca iburst prefer | |
| server ntp3.torix.ca iburst prefer | |
| server ntp.ovh.net iburst prefer | |
| server ntp.wetmore.ca iburst prefer | |
| server ntp.ymartin.com iburst prefer | |
| server tick.nrc.ca iburst prefer | |
| server tick.umanitoba.ca iburst prefer | |
| server tick.usask.ca iburst prefer | |
| server tock.nrc.ca iburst prefer | |
| server tock.usask.ca iburst prefer | |
| # --------------- | |
| # US Govt / Military Stratum 1 Peers | |
| # --------------- | |
| server ntp2.usno.navy.mil iburst | |
| server tick.usno.navy.mil iburst | |
| server time.nist.gov iburst | |
| server tock.usno.navy.mil iburst | |
| # --------------- | |
| # Other Stratum 1 Peers | |
| # --------------- | |
| server clock.isc.org iburst | |
| server cronos.cenam.mx iburst | |
| server gnomon.cc.columbia.edu iburst | |
| server hora.roa.es iburst | |
| server minuto.roa.es iburst | |
| server navobs1.wustl.edu iburst | |
| server now.okstate.edu iburst | |
| server ntp1.fau.de iburst | |
| server ntp1.inrim.it iburst | |
| server ntp1.nl.uu.net iburst | |
| server ntp1.oma.be iburst | |
| server ntp2.fau.de iburst | |
| server ntp2.inrim.it iburst | |
| server ntp2.oma.be iburst | |
| server ntp.colby.edu iburst | |
| server ntp.fizyka.umk.pl iburst | |
| server ntp-galway.hea.net iburst | |
| server ntp.i2t.ehu.eus iburst | |
| server ntp.lcf.mx iburst | |
| server ntp.neel.ch iburst | |
| server ntp.neu.edu.cn iburst | |
| server ntp.nic.cz iburst | |
| server ntp.nict.jp iburst | |
| server ntps1-0.cs.tu-berlin.de iburst | |
| server ntps1-0.uni-erlangen.de | |
| server ntps1-1.cs.tu-berlin.de iburst | |
| server ntps1-1.uni-erlangen.de | |
| server ntp-s1.cise.ufl.edu iburst | |
| server ntps1.pads.ufrj.br iburst | |
| server ntp.shoa.cl iburst | |
| server ptbtime1.ptb.de iburst | |
| server ptbtime2.ptb.de iburst | |
| server rustime01.rus.uni-stuttgart.de iburst | |
| server rustime02.rus.uni-stuttgart.de iburst | |
| server sesku.planeacion.net iburst | |
| server time1.stupi.se iburst | |
| server time.esa.int iburst | |
| server time.ufe.cz iburst | |
| server zeit.fu-berlin.de iburst | |
| # --------------- | |
| # Stratum 2 Peers | |
| # --------------- | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!! NO STRATUM 2 PEERS TO BE ENABLED ON THIS SERVER !!!!! | |
| # !!!!! THIS SERVER IS LISTED AS A STRATUM 2 POOL SERVER A !!!!! | |
| # !!!!! NTP.ORG - THEREFORE ALL PEERS *HAVE* TO BE STRATUM 1 !!!!! | |
| # !!!!! SEE http://support.ntp.org/bin/view/Servers/PublicTimeServer001302 !!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # Disabled Local fall-back if no external peers are reachable | |
| # Stratum 16 means this server is unsynchronized | |
| #server 127.127.1.0 | |
| #fudge 127.127.1.0 stratum 16 | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! |
sanyalnet-cloud-vps2.freeddns.org
sanyalnet-cloud-vps2.freeddns.org is another free public stratum-2 NTP server running on a different CentOS 7 virtual machine in a data-center in Kitchener in Ontario, Canada, using this /etc/ntp.conf:
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| # -- | |
| # This is Supratim Sanyal's NTP Server configuration file | |
| # To test, use "ntpdate -q <this host>" from another host | |
| # This server will not respond to peer queries ("ntpdc -q") etc. from | |
| # external hosts. | |
| # | |
| # The stratum 1 servers used by this server are mostly educational and | |
| # military servers from: | |
| # http://support.ntp.org/bin/view/Servers/StratumOneTimeServers?redirectedfrom=Servers.StratumOne | |
| # Comment out the stratum 2 servers to make this server stratum 2 with | |
| # only stratum 1 peers. All configured peer servers in this file need to | |
| # be stratum 1 servers for this server to be stratum 2. | |
| # Do not use burst, but iburst is ok with most stratum 1 servers. | |
| # | |
| # Supratim Sanyal, supratim at riseup dot net | |
| # ++ | |
| driftfile /var/lib/ntp/drift | |
| restrict default kod nomodify notrap nopeer noquery | |
| restrict -6 default kod nomodify notrap nopeer noquery | |
| restrict 127.0.0.1 | |
| restrict -6 ::1 | |
| # --------------- | |
| # Supratim Sanyal's Free Public NTP Servers | |
| # Stratum 2 Peers | |
| # --------------- | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!! NO STRATUM 2 PEERS TO BE ENABLED ON THIS SERVER !!!!! | |
| # !!!!! THIS SERVER IS LISTED AS A STRATUM 2 SERVER AT !!!!! | |
| # !!!!! NTP.ORG - THEREFORE ALL PEERS *HAVE* TO BE STRATUM 1 !!!!! | |
| # !!!!! SEE http://support.ntp.org/bin/view/Servers/PublicTimeServer001304 !!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | |
| # ##### -- exclude this server as peer of itself! -- server sanyalnet-cloud-vps2.freeddns.org burst iburst | |
| # ##### server sanyalnet-cloud-vps.freeddns.org burst iburst | |
| # ##### server sanyalnet-ntp.freeddns.org burst iburst prefer | |
| # ##### server wbri.duckdns.org burst iburst | |
| # ##### server yiradio.insidewashington.net burst iburst | |
| # --------------- | |
| # Stratum 1 Peers | |
| # --------------- | |
| # Preferred | |
| server time.nist.gov iburst prefer | |
| server tick.usno.navy.mil iburst prefer | |
| server tock.usno.navy.mil iburst prefer | |
| server ntp2.usno.navy.mil iburst prefer | |
| # Other | |
| server clock.isc.org iburst | |
| server clock.uregina.ca iburst | |
| server cronos.cenam.mx iburst | |
| server gnomon.cc.columbia.edu iburst | |
| server hora.roa.es iburst | |
| server minuto.roa.es iburst | |
| server navobs1.gatech.edu iburst | |
| server navobs1.oar.net iburst | |
| server navobs1.wustl.edu iburst | |
| server now.okstate.edu iburst | |
| server ntp1.fau.de iburst | |
| server ntp1.inrim.it iburst | |
| server ntp1.nl.uu.net iburst | |
| server ntp1.oma.be iburst | |
| server ntp1.usv.ro iburst | |
| server ntp2.fau.de iburst | |
| server ntp2.inrim.it iburst | |
| server ntp2.oma.be iburst | |
| server ntp.atomki.mta.hu iburst | |
| server ntp.colby.edu iburst | |
| server ntp.fizyka.umk.pl iburst | |
| server ntp-galway.hea.net iburst | |
| server ntp.i2t.ehu.eus iburst | |
| server ntp.lcf.mx iburst | |
| server ntp.neel.ch iburst | |
| server ntp.neu.edu.cn iburst | |
| server ntp.nic.cz iburst | |
| server ntp.nict.jp iburst | |
| server ntps1-0.cs.tu-berlin.de iburst | |
| server ntps1-0.uni-erlangen.de | |
| server ntps1-1.cs.tu-berlin.de iburst | |
| server ntps1-1.uni-erlangen.de | |
| server ntp-s1.cise.ufl.edu iburst | |
| server ntps1.pads.ufrj.br iburst | |
| server ntp.shoa.cl iburst | |
| server ptbtime1.ptb.de iburst | |
| server ptbtime2.ptb.de iburst | |
| server rustime01.rus.uni-stuttgart.de iburst | |
| server rustime02.rus.uni-stuttgart.de iburst | |
| server sesku.planeacion.net iburst | |
| server tick.usask.ca iburst | |
| server time1.stupi.se iburst | |
| server time.esa.int iburst | |
| server time.ufe.cz iburst | |
| server tock.usask.ca iburst | |
| server zeit.fu-berlin.de iburst | |
| # Local fall back if no external peers are reachable | |
| # Stratum 16 means this server is unsynchronized | |
| server 127.127.1.0 | |
| fudge 127.127.1.0 stratum 16 |
Again, for security, NTP queries work only from localhost:
# ntpq -p 127.0.0.1To check if the NTP server is active and serving time to external hosts over the internet, execute a ntpdate query from an external system:
# ntpdc -p 127.0.0.1
# ntpdate -q 64.137.228.122 # Command Issued on Remote System
server 64.137.228.122, stratum 2, offset 0.016148, delay 0.02615
27 Mar 02:20:06 ntpdate[22790]: adjust time server 64.137.228.122 offset 0.016148 sec
Watch this server serving time to external clients:
# nice -n 19 ionice -c3 tshark -i br0 -Y ntp | egrep "64.137.228.122 ->" | egrep "server"
Monitor time sources this NTP server obtains time from:
# nice -n 19 ionice -c3 tshark -i br0 -Y ntp | egrep "client"
sanyalnet-ntp.freeddns.org
This free public NTP server is actually running on a pfSense (based on FreeBSD) virtual machine that is my primary home internet entry point serving as the first of a custom three-level internet security and unified threat management system and firewall home internet gateway. It is a free public stratum-2 NTP server. The configuration file /var/etc/ntpd.conf is created from the pfSense saved configuration, dynamically at boot time or on changing the pfSense NTP configuration via the pfSense web interface.
tshark is not included in the standard pfSense installation. To monitor NTP traffic, use tcpdump on the WAN interfaces, similar to:
You can also monitor outgoing NTP responses to external clients by filtering the tcpdump output for the word "Server". Conversely, you can monitor the time sources this server is synchronizing itself with using the filter "Client".
tshark is not included in the standard pfSense installation. To monitor NTP traffic, use tcpdump on the WAN interfaces, similar to:
nice -19 tcpdump -i em2 udp port 123 | grep " > "
You can also monitor outgoing NTP responses to external clients by filtering the tcpdump output for the word "Server". Conversely, you can monitor the time sources this server is synchronizing itself with using the filter "Client".
nice -19 tcpdump -i em2 udp port 123 | grep " > " | grep "Server"
nice -19 tcpdump -i em2 udp port 123 | grep "Client"
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| # | |
| # pfSense ntp configuration file | |
| # | |
| tinker panic 0 | |
| # Orphan mode stratum | |
| tos orphan 16 | |
| # Upstream Servers | |
| server time.nist.gov iburst maxpoll 9 prefer | |
| server tick.usno.navy.mil iburst maxpoll 9 prefer | |
| server tock.usno.navy.mil iburst maxpoll 9 prefer | |
| server ntp2.usno.navy.mil iburst maxpoll 9 prefer | |
| server ptbtime1.ptb.de iburst maxpoll 9 | |
| server ptbtime2.ptb.de iburst maxpoll 9 | |
| server rustime01.rus.uni-stuttgart.de iburst maxpoll 9 | |
| server rustime02.rus.uni-stuttgart.de iburst maxpoll 9 | |
| server time.apple.com iburst maxpoll 9 | |
| server ntps1-0.cs.tu-berlin.de iburst maxpoll 9 | |
| statsdir /var/log/ntp | |
| logconfig =syncall +clockall +peerall +sysall | |
| driftfile /var/db/ntpd.drift | |
| restrict default kod limited nomodify noquery nopeer notrap | |
| restrict -6 default kod limited nomodify noquery nopeer notrap | |
| restrict 127.0.0.1 mask 255.0.0.0 |
Stratum-3 Free Public NTP Servers
The free public stratum-3 NTP servers I maintain, including wbri.duckdns.org, yiradio.duckdns.org etc., are Linux CentOS 7 virtual machines serving NTP usually at stratum 3 using the /etc/ntp.conf configuration file below. This NTP configuration prefers my stratum-2 servers as preferred time sources, along with free public stratum-1 servers as secondary sources. If all the stratum-2 servers become unusable in this configuration, the NTP server will then become a stratum-2 server itself, since it will use only stratum-1 servers then.
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| # -- | |
| # This is Supratim Sanyal's NTP Server configuration file | |
| # To test, use "ntpdate -q <this host>" from another host | |
| # This server will not respond to peer queries ("ntpdc -q") etc. from | |
| # external hosts. | |
| # | |
| # The stratum 1 servers used by this server are mostly educational and | |
| # military servers from: | |
| # http://support.ntp.org/bin/view/Servers/StratumOneTimeServers?redirectedfrom=Servers.StratumOne | |
| # Comment out the stratum 2 servers to make this server stratum 2 with | |
| # only stratum 1 peers. All configured peer servers in this file need to | |
| # be stratum 1 servers for this server to be stratum 2. | |
| # Do not use burst, but iburst is ok with most stratum 1 servers. | |
| # | |
| # Supratim Sanyal, supratim at riseup dot net | |
| # ++ | |
| driftfile /var/lib/ntp/drift | |
| restrict default kod nomodify notrap nopeer noquery | |
| restrict -6 default kod nomodify notrap nopeer noquery | |
| restrict 127.0.0.1 | |
| restrict -6 ::1 | |
| # --------------- | |
| # Supratim Sanyal's Free Public NTP Servers | |
| # Stratum 2 Peers | |
| # --------------- | |
| server sanyalnet-cloud-vps.freeddns.org burst iburst prefer | |
| server sanyalnet-cloud-vps2.freeddns.org burst iburst prefer | |
| server sanyalnet-ntp.freeddns.org burst iburst prefer | |
| # --------------- | |
| # Stratum 1 Peers | |
| # --------------- | |
| # Preferred | |
| server time.nist.gov iburst | |
| server tick.usno.navy.mil iburst | |
| server tock.usno.navy.mil iburst | |
| server ntp2.usno.navy.mil iburst | |
| # Other | |
| server clock.isc.org iburst | |
| server clock.uregina.ca iburst | |
| server cronos.cenam.mx iburst | |
| server gnomon.cc.columbia.edu iburst | |
| server hora.roa.es iburst | |
| server minuto.roa.es iburst | |
| server navobs1.gatech.edu iburst | |
| server navobs1.oar.net iburst | |
| server navobs1.wustl.edu iburst | |
| server now.okstate.edu iburst | |
| server ntp1.fau.de iburst | |
| server ntp1.inrim.it iburst | |
| server ntp1.nl.uu.net iburst | |
| server ntp1.oma.be iburst | |
| server ntp1.usv.ro iburst | |
| server ntp2.fau.de iburst | |
| server ntp2.inrim.it iburst | |
| server ntp2.oma.be iburst | |
| server ntp.atomki.mta.hu iburst | |
| server ntp.colby.edu iburst | |
| server ntp.fizyka.umk.pl iburst | |
| server ntp-galway.hea.net iburst | |
| server ntp.i2t.ehu.eus iburst | |
| server ntp.lcf.mx iburst | |
| server ntp.neel.ch iburst | |
| server ntp.neu.edu.cn iburst | |
| server ntp.nic.cz iburst | |
| server ntp.nict.jp iburst | |
| server ntps1-0.cs.tu-berlin.de iburst | |
| server ntps1-0.uni-erlangen.de | |
| server ntps1-1.cs.tu-berlin.de iburst | |
| server ntps1-1.uni-erlangen.de | |
| server ntp-s1.cise.ufl.edu iburst | |
| server ntps1.pads.ufrj.br iburst | |
| server ntp.shoa.cl iburst | |
| server ptbtime1.ptb.de iburst | |
| server ptbtime2.ptb.de iburst | |
| server rustime01.rus.uni-stuttgart.de iburst | |
| server rustime02.rus.uni-stuttgart.de iburst | |
| server sesku.planeacion.net iburst | |
| server tick.usask.ca iburst | |
| server time1.stupi.se iburst | |
| server time.apple.com iburst | |
| server time.esa.int iburst | |
| server time.ufe.cz iburst | |
| server tock.usask.ca iburst | |
| server zeit.fu-berlin.de iburst | |
| # Local fall back if no external peers are reachable | |
| # Stratum 16 means this server is unsynchronized | |
| server 127.127.1.0 | |
| fudge 127.127.1.0 stratum 16 |
Solaris 11 OpenIndiana NTP Time Server
I run a hobbyist Solaris 11 OpenIndiana server inside my local area network. The NTP configuration file for Solaris 11 resides in /etc/inet/ntp.conf. Since the Solaris server is inside my LAN, it can access the other LAN-only NTP servers directly as the primary time source, including the Sophos 9 UTM and ClearOS servers that form the 2nd and 3rd layers of my 3-layer home internet security system. As mentioned before, the first layer is the internet-exposed pfSense server. Here is what I use for NTP configuration for the Solaris 11 server.
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| # -- | |
| # /etc/inet/ntp.conf | |
| # This is Supratim Sanyal's NTP Server configuration file for | |
| # SunOS solaris11-3.sanyalnet.lan 5.11 11.3 i86pc i386 i86pc | |
| # | |
| # To test, use "ntpdate -q <this host>" from another host | |
| # This server will not respond to peer queries ("ntpdc -q") etc. from | |
| # external hosts. | |
| # | |
| # The stratum 1 servers used by this server are mostly educational and | |
| # military servers from: | |
| # http://support.ntp.org/bin/view/Servers/StratumOneTimeServers?redirectedfrom=Servers.StratumOne | |
| # Comment out the stratum 2 servers to make this server stratum 2 with | |
| # only stratum 1 peers. All configured peer servers in this file need to | |
| # be stratum 1 servers for this server to be stratum 2. | |
| # Do not use burst, but iburst is ok with most stratum 1 servers. | |
| # | |
| # Supratim Sanyal, supratim at riseup dot net | |
| # ++ | |
| # ----- | |
| # Workaround for unstable clock in virtual machine | |
| # ----- | |
| tinker panic 0 | |
| driftfile /var/ntp/ntp.drift | |
| restrict default kod nomodify notrap nopeer noquery | |
| restrict -6 default kod nomodify notrap nopeer noquery | |
| restrict 127.0.0.1 | |
| restrict -6 ::1 | |
| # --------------- | |
| # LAN NTP servers | |
| # --------------- | |
| server clearos-firewall burst iburst prefer | |
| server sophos-utm-firewall burst iburst prefer | |
| server pfsense-firewall burst iburst prefer | |
| # --------------- | |
| # Supratim Sanyal's Free Public NTP Servers | |
| # Stratum 2 Peers | |
| # --------------- | |
| server glewlwyd.duckdns.org burst iburst | |
| server sanyalnet-cloud-vps.freeddns.org burst iburst | |
| server sanyalnet-cloud-vps2.freeddns.org burst iburst | |
| server wbri.duckdns.org burst iburst | |
| server yiradio.insidewashington.net burst iburst | |
| # --------------- | |
| # Stratum 1 Peers | |
| # --------------- | |
| server time.nist.gov iburst | |
| server tick.usno.navy.mil iburst | |
| server tock.usno.navy.mil iburst | |
| server ntp2.usno.navy.mil iburst | |
| # Other | |
| server clock.isc.org iburst | |
| server clock.uregina.ca iburst | |
| server cronos.cenam.mx iburst | |
| server gnomon.cc.columbia.edu iburst | |
| server hora.roa.es iburst | |
| server minuto.roa.es iburst | |
| server navobs1.gatech.edu iburst | |
| server navobs1.oar.net iburst | |
| server navobs1.wustl.edu iburst | |
| server now.okstate.edu iburst | |
| server ntp1.fau.de iburst | |
| server ntp1.inrim.it iburst | |
| server ntp1.nl.uu.net iburst | |
| server ntp1.oma.be iburst | |
| server ntp1.usv.ro iburst | |
| server ntp2.fau.de iburst | |
| server ntp2.inrim.it iburst | |
| server ntp2.oma.be iburst | |
| server ntp.atomki.mta.hu iburst | |
| server ntp.colby.edu iburst | |
| server ntp.fizyka.umk.pl iburst | |
| server ntp-galway.hea.net iburst | |
| server ntp.i2t.ehu.eus iburst | |
| server ntp.lcf.mx iburst | |
| server ntp.neel.ch iburst | |
| server ntp.neu.edu.cn iburst | |
| server ntp.nic.cz iburst | |
| server ntp.nict.jp iburst | |
| server ntps1-0.cs.tu-berlin.de iburst | |
| server ntps1-0.uni-erlangen.de | |
| server ntps1-1.cs.tu-berlin.de iburst | |
| server ntps1-1.uni-erlangen.de | |
| server ntp-s1.cise.ufl.edu iburst | |
| server ntps1.pads.ufrj.br iburst | |
| server ntp.shoa.cl iburst | |
| server ptbtime1.ptb.de iburst | |
| server ptbtime2.ptb.de iburst | |
| server rustime01.rus.uni-stuttgart.de iburst | |
| server rustime02.rus.uni-stuttgart.de iburst | |
| server sesku.planeacion.net iburst | |
| server tick.usask.ca iburst | |
| server time1.stupi.se iburst | |
| server time.apple.com iburst | |
| server time.esa.int iburst | |
| server time.ufe.cz iburst | |
| server tock.usask.ca iburst | |
| server zeit.fu-berlin.de iburst | |
| # Local fall back if no external peers are reachable | |
| # Stratum 16 means this server is unsynchronized | |
| server 127.127.1.0 | |
| fudge 127.127.1.0 stratum 16 |
Digital DEC OpenVMS 7.3 VAX TCPIP NTP Time Server
My hobbyist OpenVMS 7.3 VAX servers QCOCAL VAXserver 3900 Series and CLOUDY VAX-11/780 run the NTP service that is included with Compaq TCP/IP Services for OpenVMS VAX Version V5.1. QCOCAL is reachable over the internet via TELNET sanyalnet-openvms-vax.freeddns.org. CLOUDY and numerous Digital machines including VAXen, PDP-11s etc. can be reached from QCOCAL over DECnet thanks to the HECnet Hobbyist DECnet project that I am very excited to be a part of.I have previously described how to install your own OpenVMS VAX server using the SIMH simulator in this post.
Here is my SYS$SPECIFIC:[TCPIP$NTP]TCPIP$NTP.CONF - the NTP configuration file on OpenVMS 7.3 VAX:
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| # Copyright 2000 Compaq Computer Corporation | |
| # Example NTP Configuration File | |
| # Rename this template to TCPIP$NTP.CONF. | |
| # See the Compaq TCP/IP Services for OpenVMS Management manual for | |
| # additional commands and detailed instructions on using this | |
| # configuration file. | |
| # The Network Time Protocol (NTP) provides synchronized timekeeping among | |
| # a set of distributed time servers and clients. The local OpenVMS host | |
| # maintains an NTP configuration file, TCPIP$NTP.CONF, of participating peers. | |
| # TCPIP$NTP.CONF is maintained in the SYS$SPECIFIC:[TCPIP$NTP] directory. | |
| # As the system manager populating this file, you must determine the | |
| # peer hosts with which the local hosts should negotiate and synchronize | |
| # Include at least one (but preferably three) hosts that you are | |
| # certain have the following characteristics: | |
| # * provide accurate time | |
| # * synchronize to Internet Time Servers (if they are not themselves | |
| # Internet Time Servers). | |
| # The NTP configuration file is not dynamic, and therefore requires | |
| # restarting NTP after being edited to make the changes take effect. | |
| # However, you can make runtime configuration requests interactively | |
| # using the TCPIP$NTPDC utility. | |
| # Your NTP configuration file should always include the following | |
| # driftfile entry. The driftfile is the name of the file that stores | |
| # the clock drift (also known as frequency error) of the system clock. | |
| driftfile SYS$SPECIFIC:[TCPIP$NTP]TCPIP$NTP.DRIFT | |
| # Samples peer entries follow. Replace them with your own list of hosts | |
| # and identify the appropriate association mode. If you specify | |
| # multiple hosts, NTP can choose the best source with which to | |
| # synchronize. This also provides reliability in case one of the hosts | |
| # becomes unavailable. | |
| # Identify each peer with a fully-qualified DNS host name or with | |
| # an IP address in dotted-quad notation. | |
| # --------------- | |
| # Supratim Sanyal's Free Public NTP Servers | |
| # Stratum 2 Peers | |
| # --------------- | |
| server sanyalnet-cloud-vps2.freeddns.org burst iburst | |
| server sanyalnet-cloud-vps.freeddns.org burst iburst | |
| server wbri.duckdns.org burst iburst | |
| server yiradio.insidewashington.net burst iburst | |
| # --------------- | |
| # Stratum 1 Peers | |
| # --------------- | |
| # Preferred | |
| server time.nist.gov iburst prefer | |
| server tick.usno.navy.mil iburst prefer | |
| server tock.usno.navy.mil iburst prefer | |
| server ntp2.usno.navy.mil iburst prefer | |
| # Other | |
| server clock.isc.org iburst | |
| server clock.uregina.ca iburst | |
| server cronos.cenam.mx iburst | |
| server gnomon.cc.columbia.edu iburst | |
| server hora.roa.es iburst | |
| server minuto.roa.es iburst | |
| server navobs1.gatech.edu iburst | |
| server navobs1.oar.net iburst | |
| server navobs1.wustl.edu iburst | |
| server now.okstate.edu iburst | |
| server ntp1.fau.de iburst | |
| server ntp1.inrim.it iburst | |
| server ntp1.nl.uu.net iburst | |
| server ntp1.oma.be iburst | |
| server ntp1.usv.ro iburst | |
| server ntp2.fau.de iburst | |
| server ntp2.inrim.it iburst | |
| server ntp2.oma.be iburst | |
| server ntp.atomki.mta.hu iburst | |
| server ntp.colby.edu iburst | |
| server ntp.fizyka.umk.pl iburst | |
| server ntp-galway.hea.net iburst | |
| server ntp.i2t.ehu.eus iburst | |
| server ntp.lcf.mx iburst | |
| server ntp.neel.ch iburst | |
| server ntp.neu.edu.cn iburst | |
| server ntp.nic.cz iburst | |
| server ntp.nict.jp iburst | |
| server ntps1-0.cs.tu-berlin.de iburst | |
| server ntps1-0.uni-erlangen.de | |
| server ntps1-1.cs.tu-berlin.de iburst | |
| server ntps1-1.uni-erlangen.de | |
| server ntp-s1.cise.ufl.edu iburst | |
| server ntps1.pads.ufrj.br iburst | |
| server ntp.shoa.cl iburst | |
| server ptbtime1.ptb.de iburst | |
| server ptbtime2.ptb.de iburst | |
| server rustime01.rus.uni-stuttgart.de iburst | |
| server rustime02.rus.uni-stuttgart.de iburst | |
| server sesku.planeacion.net iburst | |
| server tick.usask.ca iburst | |
| server time1.stupi.se iburst | |
| server time.apple.com iburst | |
| server time.esa.int iburst | |
| server time.ufe.cz iburst | |
| server tock.usask.ca iburst | |
| server zeit.fu-berlin.de iburst | |
| # The following commands allow interoperation of NTP with another time service | |
| # such as DTSS. If enabled (by removing #), NTP will not set the system clock. | |
| # server 127.127.1.0 prefer | |
| # fudge 127.127.1.0 stratum 0 | |
| # The following commands allow this node to act as a backup NTP server (or as | |
| # the sole NTP server on an isolated network), using its own system clock as | |
| # the reference source. If enabled (by removing #), this NTP server will | |
| # become active only when all other normal synchronization sources are | |
| # unavailable. | |
| server 127.127.1.0 | |
| fudge 127.127.1.0 stratum 16 |
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