--- tags: PMC-100 --- # NTP configuration ``` ### Update ubuntu sudo apt-get update ### install NTP sudo apt-get install ntp ### If issue in installing ntp and update 1. ps aux | grep -i apt 2. sudo killall apt apt-get 3. echo "nameserver 8.8.8.8" | sudo tee /etc/resolv.conf > /dev/null ### Start NTP server sudo systemctl enable ntp sudo systemctl start ntp sudo systemctl status ntp ### testing ntp server 1. ntpq -p ``` ### NTP file and location ``` 1. drift --> cat /var/lib/ntp/ntp.drift 2. config --> cat /etc/ntp.conf ``` ### Useful commands 1. firewall ntp udp rule --> `grep -E -w '123/udp' /etc/services` 2. update server once changes done --> `ntpdate 10.10.80.106` 3. verify authentication --> `ntpq -c authinfo` ### Testing NTP Server and client 1. Change the time or date in server * timedatectl set-time 12:00:00 * timedatectl set-ntp 0 --> automatic ntp off * timedatectl set-ntp 1 --> automatic ntp on * LC_TIME=en_US.utf8 (time language change) # Reference 1. [Config ntp server ](https://kifarunix.com/install-and-setup-ntp-server-on-ubuntu-22-04-debian-11/) 2. [Config ntp client ](https://kifarunix.com/install-and-configure-ntp-client-on-ubuntu-debian-systems/) 3. [Will help for firwall issue](https://linuxhint.com/setup-ntp-server-and-client-on-ubuntu/) 4. [NTP server pool](https://www.pool.ntp.org/zone/tw) 5. [NTP command link](https://manpages.ubuntu.com/manpages/xenial/man5/ntp.conf.5.html) 6. [To understand ntp peer details](https://timetoolsltd.com/ntp/how-to-install-and-configure-ntp-on-linux/) 7. [Understand the NTP process](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/s1-understanding_leap_seconds) 8. [Debugging issue](https://luppeng.wordpress.com/2020/02/05/using-an-undisciplined-local-clock-to-cause-ntpd-to-exit-panic-and-how-to-recover-from-it/)