NTP: Difference between revisions
imported>Tobias.bora No edit summary |
imported>IgorM m Fixed syntax highlighting errors by using lang=text where it was omitted |
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Most of the time the default NTP servers will be reachable. However, sometimes the NTP servers can be blocked by the firewall (for instance most universities block NTP for security reasons). This will be visible in the <code>systemd-timesyncd.service</code>: | Most of the time the default NTP servers will be reachable. However, sometimes the NTP servers can be blocked by the firewall (for instance most universities block NTP for security reasons). This will be visible in the <code>systemd-timesyncd.service</code>: | ||
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$ sudo systemctl status systemd-timesyncd.service | $ sudo systemctl status systemd-timesyncd.service | ||
● systemd-timesyncd.service - Network Time Synchronization | ● systemd-timesyncd.service - Network Time Synchronization | ||
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You can also test a specific server as follows: | You can also test a specific server as follows: | ||
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$ nix-shell -p ntp | $ nix-shell -p ntp | ||
$ ntpdate -q 0.nixos.pool.ntp.org | $ ntpdate -q 0.nixos.pool.ntp.org | ||
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However, a replacement NTP is usually provided in that case via the DHCP protocol. You can see it for instance if you use Network Manager: | However, a replacement NTP is usually provided in that case via the DHCP protocol. You can see it for instance if you use Network Manager: | ||
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$ nmcli connection show 'name-of-the-current-connection' | grep ntp | $ nmcli connection show 'name-of-the-current-connection' | grep ntp | ||
DHCP4.OPTION[8]: ntp_servers = 192.168.x.y | DHCP4.OPTION[8]: ntp_servers = 192.168.x.y | ||
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You might also be able to get the actual hostname of the DHCP (if it exists) using: | You might also be able to get the actual hostname of the DHCP (if it exists) using: | ||
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$ sudo nmap -sP 192.168.x.y | $ sudo nmap -sP 192.168.x.y | ||
</syntaxHighlight> | </syntaxHighlight> | ||