timedatectl set-ntp no
apt install ntp -y


ntpq -p

Optional change ntp.conf to Use pooling instead of servers:

vi /etc/ntp.conf

pool pool.ntp.org

minpoll 4
maxpoll 9

tos minclock 4 minsane 3 
tos maxclock 8

clock peer sync sys

info events status statistics
logconfig =allall
statsdir /var/lib/ntp/stats
logfile /var/log/ntp

driftfile /var/lib/ntp/drift

pidfile /var/run/ntpd.pid

restrict default limited kod nomodify notrap nopeer noquery
restrict -6 default limited kod nomodify notrap nopeer noquery
restrict ::1
restrict source limited kod nomodify notrap noquery
service ntp restart


ntpq -p

if you have a service like database,….. which needs to start after time synchronization, consider using command : /usr/sbin/ntp-wait -n 10 -s 2 -v


the line

/usr/sbin/ntp-wait -v

-may cause delay on services start, up to 10 minutes

-the command may fail on Correct Time or Failed time Sync

if you can’t wait, force time sync with:

ntpdate -u pool.ntp.org

Note: if you are setting a wrong time to test the ntpd, consider this:

ntpd will refuse to set the clock if it’s too far out, and will just exit. I guess it’s to protect against some rogue NTP server giving it bogus time information. If a time server goes wrong and gives you info that is weeks/months/years out, it could cause havok for your server.

for testing purpose set the time to something nearly correct manually.


I’m in mood, so writing this note

having a correct time is important, but its dangerous for modern applications which produces/consumes data or services based on time. time attacks which can change the time on your server withing ntp or somehow you don’t know, will cause wrong data produce/consume/store.

if your are worry about this , consider writing a time travel detector script or program to avoid this attacks.

By: Mehdi Sadighian
Contact: mehdi.sadighian@hotmail.com
TAG: slackware, ntp, ntpd, continuous time sync