https://www.linuxhosted.com/tags/time-synchronization/Recent content in Time Synchronization on LinuxHosted.comHugo -- gohugo.ioenLinuxHosted.comTue, 10 Nov 2026 00:00:00 +0000https://www.linuxhosted.com/post/how-to-sync-server-time-with-chrony-ubuntu/Tue, 10 Nov 2026 00:00:00 +0000https://www.linuxhosted.com/post/how-to-sync-server-time-with-chrony-ubuntu/ <p>Ubuntu uses chrony to keep the system clock in sync, and <a href="https://ubuntu.com/server/docs/how-to/networking/chrony-client/">chrony is installed by default as of Ubuntu 25.10</a>. On older releases <a href="https://ubuntu.com/server/docs/how-to/networking/timedatectl-and-timesyncd/">systemd-timesyncd was the default</a>, and chrony takes one <code>apt</code> command to install.</p> <hr> <h2 id="where-clock-errors-and-time-jumps-show-up">Where Clock Errors and Time Jumps Show Up</h2> <h3 id="tls-certificates">TLS certificates</h3> <p>Every X.509 certificate carries <a href="https://www.rfc-editor.org/rfc/rfc5280.html">a validity period, from notBefore to notAfter</a>. Path validation checks that this period includes the current time, and &quot;current time&quot; means whatever the server's clock says. A VPS running days behind can reject a certificate issued yesterday as not yet valid. A VPS running far ahead can treat a valid certificate as expired.</p>