The Network Time Protocol, is used to synchronize system clocks to precision time servers on the internet or locally connected devices such as a GPS.
Questions tagged [ntp]
311 questions
14
votes
2 answers
ntpdate -d seems successful, but ntpdate returns no server suitable
I've got a system that is not running ntpd on which I'm attempting to update the clock using ntpdate. The system is an appliance that appears to be CentOS 6 based.
When I run ntpdate 0.pool.ntp.org, I get:
8 Sep 17:52:05 ntpdate[7445]: no server…
csyria
- 265
6
votes
2 answers
Time synchronization of machines on LAN to GPS NTP server on the LAN
I have 4 computers on a LAN that need to have their system clocks closely synchronized within a ms or so if possible. I have just installed a GPS based time server (ESE-104A) on the LAN. At this point the LAN is connected to a router and the…
Nate Lockwood
- 193
- 1
- 9
6
votes
2 answers
ntp.conf peer vs server
I'm setting up an NTP server (one of what will be five in a cluster). My config file:
restrict default kod nomodify notrap
driftfile /var/lib/ntp/drift
server tick.usno.navy.mil
server ntp.colby.edu
server tick.gatech.edu
#peer…
theillien
- 1,308
5
votes
1 answer
128 bit timestamp in NTP queries
Wikipedia claims that NTPv4 supports 128-bit timestamps and indeed RFC5905 defines a 128-bit format called "NTP Date Format" in Sect. 6. The RFC says
The 128-bit date format is used where sufficient storage and word
size are available.
However,…
Jonas Mechtheim
- 147
3
votes
1 answer
Does ntpd default allow query requests through?
I am confused as to what is the default access policy of an ntp server. According to the ntp_acc man page, access can only be denied if specifically blacklisted.
Clients can be denied service because they are explicitly included in
the restrict…
Jason Zhu
- 261
2
votes
0 answers
is there a generic way to check if time is synchronised
I am writing some software that runs on a system that may or may not have access to the internet and I want it to behave differently depending on whether the clock is synchronised, It will likely run on a Debian-based distro, but exactly which one…
plugwash
- 4,352
2
votes
0 answers
Why does ntpdate -q 127.0.0.1 give any offset error?
When I run ntpdate -q 127.0.0.1 I get:
server 127.0.0.1, stratum 3, offset -0.000013, delay 0.02573
28 Apr 17:30:41 ntpdate[27944]: adjust time server 127.0.0.1 offset -0.000013 sec
Why does it register an offset of -0.000013 sec considering the…
2
votes
0 answers
NTPD fails to find valid peers
I have a couple of Ubuntu servers that time and time again only receive peers with a stratum of 16. If I restart the ntp daemon a couple of times, eventually I will get one or two usable peers (with stratum 1 or 2).
I fail to find out why so often I…
Paul
- 21
2
votes
1 answer
How can I stop NTP from updating my system clock?
I have a Debian Jessie Linux system with an internal RTC clock which the user can adjust or change. It may or may not be connected to external IP and therefore may or may not have access to NTP. I would like to provide an option in the clock setting…
Dave Lawrence
- 149
2
votes
2 answers
NTP Servers not Sync with other machines
I'm using Linux Debian Wheezy.I have problem to sync time & date between my server & PC,and the ntp servers looks like pointing at itself not internet.
In this case,Fig is my NTP server.
root@fig [5156]# ntpq -p
remote refid st…
Kamal
- 53
2
votes
2 answers
Best practice for setting time on local network using NTP
I have 13 computers in the office that I want to make sure the time is in sync. I thought of configuring a virtual server to be the NTP server of the local network. That NTP server will sync with the pool of servers. On the clients, would it be okay…
tomhauss13
- 21
- 1
- 2
2
votes
2 answers
How do you deal with unreliable NTP peers?
I ran lynis 1.5.6 and got the following log message.
Performing test ID TIME-3120 (Check unreliable NTP peers)
Test: Checking unreliable ntp peers
Result: Found one or more unreliable peers (marked with a minus or dash sign)
Unreliable peer:…
OtagoHarbour
- 785
- 4
- 13
- 28
1
vote
1 answer
Error compiling NTPv4 for ARM with OpenSSL
The error is along the lines of
"ntp_crypto.c:2248:2: error: unknown type name 'DSA_SIG'; did you mean 'ECDSA_SIG'?"
make fails with the following output:
tp_crypto.c: In function 'crypto_alice':
ntp_crypto.c:2188:13: warning: implicit declaration…
1
vote
1 answer
Understanding configuration of NTP server
I opened /etc/ntp.conf file. I have the following entries:
server 0.centos.pool.ntp.org
restrict 0.centos.pool.ntp.org mask 255.255.255.255
I am not sure what mask 255.255.255.255 is doing exactly? I read some posts (post) around but still not…
Avv
- 113
1
vote
1 answer
Crazy clock drift on ancient VM
I am stuck with a Centos 5.3 VM (running on Proxmox) which exhibits huge clock drift. It was configured to run ntpdate every 5 minutes but the clock was still getting out of sync by up to 20 seconds between executions. I've tried running ntpd (and…
symcbean
- 5,540