Example Chrony config

chrony.conf

@@ -0,0 +1,64 @@
+# Welcome to the chrony configuration file. See chrony.conf(5) for more
+# information about usable directives.
+
+# Use Debian vendor zone.
+#pool 2.debian.pool.ntp.org iburst
+
+# Use time sources from DHCP.
+sourcedir /run/chrony-dhcp
+
+# Use NTP sources found in /etc/chrony/sources.d.
+sourcedir /etc/chrony/sources.d
+
+# This directive specifies the location of the file containing ID/key pairs for
+# NTP authentication.
+keyfile /etc/chrony/chrony.keys
+
+# This directive specifies the file into which chronyd will store the rate
+# information.
+driftfile /var/lib/chrony/chrony.drift
+
+# Save NTS keys and cookies.
+ntsdumpdir /var/lib/chrony
+
+# Uncomment the following line to turn logging on.
+#log tracking measurements statistics
+
+# Log files location.
+logdir /var/log/chrony
+
+# Stop bad estimates upsetting machine clock.
+maxupdateskew 100.0
+
+# This directive enables kernel synchronisation (every 11 minutes) of the
+# real-time clock. Note that it can't be used along with the 'rtcfile' directive.
+rtcsync
+
+# Step the system clock instead of slewing it if the adjustment is larger than
+# one second, but only in the first three clock updates.
+makestep 1 3
+
+# Get TAI-UTC offset and leap seconds from the system tz database.
+# This directive must be commented out when using time sources serving
+# leap-smeared time.
+leapseclist /usr/share/zoneinfo/leap-seconds.list
+
+# Include configuration files found in /etc/chrony/conf.d.
+#confdir /etc/chrony/conf.d
+
+
+# ACL
+# I have set it to RFC1918 because I'm using my firewall to explicitly allow access to NTP server
+allow 192.168.0.0/16
+allow 10.0.0.0/8
+allow 172.16.0.0/12
+
+# Explicitly tell clients that we are stratum 1
+local stratum 1
+
+
+# Onboard GPS clock
+
+#refclock SHM 0 refid NMEA offset 0.000 precision 1e-3 poll 3 noselect
+refclock SHM 0 refid NMEA offset 0.125 precision 1e-3 poll 3 noselect
+refclock PPS /dev/pps0 refid PPS lock NMEA poll 3