mjhjmtu

How to get a working clock in Debian 9 with KDE? My clock is almost 10 minutes slow on multiple of my machines running Debian 9 with KDE and (re)setting the timezone via tzselect didn't work.

(I already solved this but maybe other people would like to have a working clock as well. Also I'm interested in other ways to solve this. I'm surprised this isn't taken care of by the default installation of Debian so that it works right away if you selected the right timezone during installation.)

1. Install openntpd: sudo apt-get install openntpd
ntp did not work and I didn't try Redhat's chrony.



2. 
   

   sudo kate /etc/openntpd/ntpd.conf and make sure there are 4 uncommented lines (replace XY with your country code):

   
   
   

   # Choose servers announced from Debian NTP Pool
   servers 0.XY.pool.ntp.org
   servers 1.XY.pool.ntp.org
   servers 2.XY.pool.ntp.org
   servers 3.XY.pool.ntp.org
   

   
   


3. 
   

   If you're using iptables add these firewall rules:

   
   
   

   -A INPUT -p udp -m udp --dport 123 -j ACCEPT
   -A INPUT -p udp -m udp --sport 123 -j ACCEPT
   -A OUTPUT -p udp -m udp --dport 123 -j ACCEPT
   -A OUTPUT -p udp -m udp --sport 123 -j ACCEPT`
   

   
   



4. sudo ntpctl -s status should return .../20 peers valid, clock synced...




5. (To correct the minutes: ntpd -s. You might have to restart the service: sudo /etc/init.d/openntpd restart)




6. (Make sure in sudo kate /etc/sysctl.d/99-sysctl.conf it says net.ipv4.tcp_timestamps=0. If it's not set change it and reboot.)




7. (If you had ntp installed before run sudo apt-get purge ntp. If you're using AppArmor follow the guide in this answer at askubuntu.)