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Questions tagged [ntp]

NTP stands for Network Time Protocol, and it is an Internet protocol used to synchronize the clocks of computers to some time reference.

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Why is the time on my Server 2008 R2 DC wrong? It's syncing to ntp.org, it claims

OK. After a lot of fun with syncing time across my workstations, I got that sorted out. My workstations are now perfectly synced with my Server 2008 R2 Domain Controller (physical server, not virtual). Unfortunately, that means all our computers are…
evilspoons
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The wisdom of 'server 127.127.1.0' in ntp.conf for virtual servers

Considering the 'undisciplined local clock' on VMs is not what you'd call accurate in most cases, how wise is it to include lines such as these in your NTP configuration? # Undisciplined Local Clock. This is a fake driver intended for backup # and…
Blue Warrior NFB
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How can I defend against a DRDoS exploiting NTP server on an ESXi host?

Recently, we had some problems with one of our ESXi servers, caused by the NTP Server DRDoS Amplification Attack using ntpdc. How do I configure the NTP server on ESXi to not be exposed to this DDoS attack? Or, if I switch off the service, will…
fefe
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DDOS using ntp server

I've heard about new kind of DDOS where ntp is used for reflection . My questions are really simple : Can you please give details on how they work and clarify? Since ntp is ran over UDP, I suppose there must be some kind of forged packet…
user130370
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Setting up NTP servers

I have a problem setting up NTP to maintain time on a stand-alone network. This will be an island time-zone. The problem is that the time drifts apart, even after they have been initially synchronised. There are two redundant NTP servers running…
DanS
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ntpdate works, but ntpd can't synchronize

This is in RHEL 5.5. First, ntpdate to the remote host works: $ ntpdate XXX.YYY.4.21 24 Oct 16:01:17 ntpdate[5276]: adjust time server XXX.YYY.4.21 offset 0.027291 sec Second, here are the server lines in my /etc/ntp.conf. All restrict lines have…
dafydd
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Is an ntpdate correction atomic?

I've got the following in /var/log/syslog, from yesterday (July 30th) Dec 16 22:54:05 omap ntpdate[432]: step time server 91.189.94.4 offset 12052648.821465 sec ntpdate 91.189.94.4 "corrected" my clock from July 30th to December 16th! According to…
Peter Woo
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NTP configuration not recognized?

I'm trying to configure NTP on my machine but it seems that the parameters I set are not being read by the system. Below is my /etc/ntp.conf file. (I applied the most basic configuration to eliminate other issues) server 10.45.68.47 server…
Eugene S
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Best practices for NTP updating in VirtualBox virtual machines without guest additions?

I have a couple of VMs that cannot have guest additions installed, and I pause and resume them with days between. I normally forget to nudge NTP when I start up the VM. Is there a good way to tell ntp to be very aggressive in how often it should…
Paul Hoffman
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ntp multicast address

A silly question probably, but guess I need to ask. If I've got four centos boxes that are acting as ntpd multicast servers, will the multicast address configured in each box's ntp.conf all be the same (like 224.0.1.1) on all four boxes? Or does…
user52874
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System clock drifting out of sync with hwclock and ntpd

My current system drifts from the hwclock and ntpd dramatically. I've looked at many forums and posts online and on SF, but haven't found a suitable solution. Here is my ntpq -pn output: remote refid st t when poll reach delay …
samxli
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SNTP, why do you mock me?

--- SOLVED SEE EDIT 5 --- My w2k3 pdc is configured as an authoritative time server. Other servers on the domain are able to sync with it if I manually specify it in the peer list. By if I try to sync from flags 'domhier', it wont resync; I get the…
Matt
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What increments stratum in NTP?

Sorry, it's just not that clear to me from the man pages, Wikipedia, etc. I understand the concept of stratum 0 as an authoritative time source and stratum 1 as the connected server. However, I am not sure what to consider for a larger network that…
Aaron Copley
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openwrt: Use rdate with NTP servers?

I've noticed that some embedded devices (such as OpenWRT, which runs on Busybox) use rdate to set the system time, instead of NTP. Rdate is an older time protocol, and I'm having trouble finding any working rdate servers in the United States. Is it…
Stefan Lasiewski
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What replaces "ntpq" in CentOS 8?

I want to install this utility ntpq as described here: https://www.cyberciti.biz/faq/linux-unix-bsd-is-ntp-client-working/ It prints all connected NTP servers and various NTP sync measurements. Cant find it for Centos.
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