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.

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How to update NTP (Network Time Protocol) on Solaris 11? Fighting with DDoS attacks

At the moment lots of servers suffers from denial of service attacks targeting NTP protocol on port 123 by issuing MONLIST requests to victims computers. Victims computers answer with large list of ...
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38 views

systemd-timesyncd on Debian 8 (fails silently?)

I'm having troubles on a Debian 8 installation to get systemd to synchronise time properly. NTP has been enabled with timedatectl set-ntp true and systemctl status systemd-timesyncd reports: ● ...
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29 views

How do I install and configure NTP on CentOS 7 from source? (include/ntp_crypt.h errors)

I unpacked the .tar.gz file for the newest NTP. I installed the gcc compiler and libcap devel. I ran the ./configure command with various flags and options. I ran make check and found an error. The ...
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31 views

How do I install NTP from source on CentOS v7? (/bin/ld: cannot find -lcap)

I unpacked the .tar.gz file. I installed the gcc compiler. I ran the ./configure command with various flags and options. I ran make check and found an error. The exit status is 2. Only 0 is ...
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3answers
35 views

Where to check ntp related logs on Sun Solaris?

Can you please guide, where on solaris i can check NTP related logs? If there is any issue related to NTP on solaris, which is the right place to check for the root cause? Thanks
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41 views

Setting time and date without using NTP

I have a "windriver" linux based Wimax ASN, and when ever I login, I find the date and time is wrong (example: "15 jul 2010"). Whenever I set both the date and time with the date command, or the ...
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2answers
65 views

NTP works but clock is not the same

I'm trying to sync multiple machines (9 machines that are cloned from one machine so they have exactly same config) on a LAN using NTP. All machines are running FreeBSD 10.2 on VirtualBox with Ubuntu ...
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1answer
58 views

Time synchronization, use NTP or just socket?

I am using a PC and a raspberry pi(both run Linux) to gather sensor data, raspberry pi gathers laser scan data, PC gathers image captured by camera. I must synchronize time for these two machines. I ...
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51 views

Multicast NTP server/client

what I have here is an NTP server (on Linux Mint) and a client (likewise). Server is configured to send a multicast message across the LAN which clients receive and update their clocks - it was ...
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1answer
24 views

How to install an NTP-server that is vulnerable to NTP-amplification

I'm trying to install an NTP-server that is vulnerable to NTP-amplification for a demo. I'm using this script to perform the demo: https://www.exploit-db.com/exploits/37562/ But I can't find any ...
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20 views

Suddenly ntpdate is synchronized that long time interval and no servers reachable

I set the ntpdate the local ntp server. Sometimes ntpd has "no servers reachable" in message logs than ntpdate is synchronized long time interval("time reset +17.412149 s"). Help me! How do i solve ...
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340 views

RTC time synchronization not working (CONFIG_RTC_SYSTOHC)

I have the option CONFIG_RTC_SYSTOHC enabled in my kernel: Device Drivers ---> [*] Real Time Clock ---> [*] Set the RTC time based on NTP synchronization The help says: ...
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34 views

Display the most accurate time possible

I want to set the time on my watch as closest as possible to the actual, synchronized, current time. Is there a command which will repeatedly display the current time down to the second, calibrated ...
4
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1answer
5k views

Why am I getting apparmor error messages in the syslog about NTP and LDAP?

On my newly installed Ubuntu 12.04 machine, with ntp and slapd installed, the following messages appear in /var/log/syslog at regular intervals: Feb 23 18:54:07 my-host kernel: [ 24.610703] ...
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2answers
104 views

sntp replacement for -P (prompt) argument

I'm maintaining some cronjobs on machines that are set to be patched to the service pack of SLES11sp4, it appears that the service pack is upgrading sntp from version 4.2.4p8 to 4.2.8p2 and somewhere ...
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1answer
25 views

Set the “-x” slewing option for NTP startup

On RedHat it can be set in /etc/sysconfig/ntpd but despite much searching on web and also reading man page for ntpd, I cannot find how you do this on Ubuntu (set -x option on ntpd). I can manually ...
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1answer
55 views

NTP server quality: low delay or low jitter?

I got two NTP servers I could use, one is Stratum two NTP, having low jitter and high delay; Second one is Stratum three NTP, having low delay but higher jitter. For the sake of accuracy, which one ...
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1answer
882 views

Chrony 506 Cannot talk to daemon

I'm having trouble configuring chrony to sync the time between my raspberry pi and a desktop computer in an isolated network. My raspberry pi's chrony.config file looks like this: server master ...
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79 views

Difference between chronyd and ntpd

What is the difference between chronyd and ntpd? I know that ntpd can gradually adjust the time so that it can converge gradually to the the reference clock. Can this be done with chrony?
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1answer
81 views

Which NTP server should I use?

I want to set up the NTP server in my servers that are located in Frankfurt, using UTC as timezone. But I don't know which NTP server should I use. This is the result from the ubuntu ntp server: ...
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4answers
11k views

timed out, nothing received

I tried all and googled a lot! But I can't make work NTP on my server. This post is last hope! I have installed ntp on debian server with this configuration (/etc/ntp.conf): driftfile ...
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2answers
186 views

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 ...
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58 views

Unable to start NTP [closed]

Last week it works correctly, but now, my virtual machine inside virtualbox out of sync by 5 minutes $ systemctl status systemd-timesyncd ● systemd-timesyncd.service - Network Time Synchronization ...
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63 views

Does ntpd have a default driftfile?

I have an embedded Linux with busybox's ntpd. My ntpd.conf is tinker panic 0 server pool.ntp.org iburst server 0.pool.ntp.org iburst server 1.pool.ntp.org iburst restrict default kod nomodify notrap ...
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193 views

How to solve the problem of ntp “Unable to contact time server” from KDE?

I want to set date and time automatically but this error appears when I try to .. I'm using openSUSE, I tried different servers but it didn't work either, help please! It doesn't seem to be a ...
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77 views

ntpd socket problem

Currently I have a C# program that queries my NTP server (CentOS 7) public static DateTime GetNetworkTime() { const string ntpServer = "192.168.10.48"; var ntpData = new byte[48]; ...
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2answers
157 views

Use default gateway as ntp server

I have a lot of servers running debian and they all must synchronize clock to NTP server running on their respective default gateway. Since there is many servers on many different network segments, I ...
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1answer
75 views

Troubleshooting GSS-API error on one client authenticating to Kerberos

When authenticating to kadmin with one client of many, it fails with kadmin: GSS-API (or Kerberos) error while initializing kadmin interface. The Kerberos host is specified with its subnet ...
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2answers
172 views

How to update NTP without shutting down the NTP daemon?

I would like to have a one-liner for updating the date via NTP getting the NTP-servers from the /etc/ntp.conf file. Especially because a manual command does not always work, because of firewall rules, ...
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215 views

How to set NTP tinker step (which unit)? and how to query?

One of the workaround for old CentOS/CentOS kernel (6.1-6.3) which may "Systems hang due to leap-second livelock." (quoting redhat), is to set tinker step in /etc/ntp.conf. Bug the documentation is ...
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88 views

Do I need to stop NTP service for client or only the server for leap second bug in linux

I have a server with suse 11 sp1 which are connected to NTP server that is also of same version. How can prevent leap second bug from effecting the servers? Can stoping the NTP service prevent effects ...
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66 views

ntpdate timeout ambiguity

Does the ntpdate option -t set the timeout in whole seconds or fractions? The man page isn't entire clear. It says -t timeout Specify the maximum time waiting for a server response as the ...
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1answer
41 views

dhcp3-server and strange DNS/NTP servers

I have problem with dhcp3-server 3.1.1-6+lenny4. My dhcp-server sends "strange" IPs for DNS and NTP servers in DHCP ACK despite configuration which doesn't have those IPs. In ACK packet we can see the ...
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1answer
163 views

NTP and NTPD Nanokernel

I had a couple of questions about the NTP Nanokernel as explained here: http://www.eecis.udel.edu/~mills/database/brief/nano/nano.pdf The big question is how does this Nanokernel manage to deliver an ...
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3k views

How to get system time with microsecond Resolution

I want to know current system time with microsecond Resolution. date +%s returns Time in seconds since epoch(1-1-1970). How can I get time in microseconds Resolution. How much delay is in querying ...
2
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1answer
291 views

NTPd Not Syncing on RaspberryPi

Since my hardware (RasberryPi) does not have a hardware-clock, each bootup warps us back to the 1970's, so I use NTP. The gateway on the network I am on provides an NTP-Server service. my ...
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2answers
85 views

Force time to stay put

The time on my Linux machine will not stay put. I need to test an issue with our server that only occurs on Saturdays. CentOS 6.5 64-bit I have NTPD off. (service ntpd stop and chkconfig ntpd off) ...
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69 views

Linux Mint system clock is days ahead after an overnight laptop suspend

I'm a long-time Ubuntu user, who recently started trying out Linux Mint on a laptop. This is not a dual-boot setup, Mint is the only OS on the machine. When I suspend the laptop (i.e. close the ...
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60 views

How can I consistently tell OpenSUSE to refresh the clock / current time?

I use OpenSUSE in a VM and sometimes want to save the machine and get back to work later. I haven't had much success with hibernate or suspend, so I simply save the state of the machine and resume ...
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1answer
39 views

What ntpq command or configuration setting would show output from a statum 1 server?

How can I tell ntpq to output servers other than stratum 2? Currently ntpq -p prints this. But what I need is at least one stratum 1 server in the output. I've read here and here. I've also tried ...
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93 views

NTP setup on a Java application Linux server

In a farm of time sensitive Java application Linux servers, how should one configure NTP in the ntp.conf file? Would it be okay to point the server to four stratum 3 NTP servers (switches) that are ...
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2answers
531 views

How long will NTP take to adjust the clock if it doesn't immediately set it?

I'm using SNTP to sync my Debian based system. SNTP has two ways to set the clock: -s, --settod Set (step) the time with settimeofday(). -j, --adjtime Set (slew) the time with adjtime(). The ...
4
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1answer
306 views

How to run ntp commands as non-root?

NTP commands such as ntpd and ntpdate are privileged and belongs to the root group. What is the best way to run these commands as non-root ? Linux capabilities, ownership, any method ? I have openSUSE ...
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1answer
755 views

Automatically update hwclock at boot

We're having a small issue with our Beagle Bone Blacks. Since they do not come with a RTC battery, when they lose power, the hardware clock gets messed up. I need a simple and clean way of syncing the ...
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113 views

script does not execute

I have rPi B+ running ArchLinux with kernel Linux comp001 3.18.6-2-ARCH #1 PREEMPT Sun Feb 8 09:43:43 MST 2015 armv6l GNU/Linux with Real Time Clock hardware RTC Pi. However, I would like to check if ...
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72 views

What causes ntpq refid CRYP when authentication is successful?

I have five servers that I'm configuring for production use based on a configuration we've recently tested. The servers are RHEL6 with NTP version 4.2.4p8@1.1612-o. Right now, though, I'm trying to ...
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1answer
35 views

Do I need nomodify set on NTP servers which are not publicly accessible?

I am configuring five new RHEL6 NTP servers. Each uses a list of five USNO servers as their source with at least one unique server one each one. Each of the five servers also peers to the others. None ...
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74 views

NTP authentication failing with opcode 108

I'm trying to get NTP authentication working on a cluster of test servers and a couple clients. I've followed the instructions at ntp.org. To be honest, though, I'm not sure they are entirely clear ...
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2answers
3k views

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 ...
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149 views

How much RAM and CPU for a NTP server? [closed]

As a side project, I am thinking about adding a NTP server to pool.ntp.org. I would like to use CentOS basic, but how much RAM and CPU should I assign to a machine that will only be running ntpd (plus ...