diff -Naur old/ntp.conf new/ntp.conf
--- old/ntp.conf	2017-01-17 12:00:15.560426583 -0600
+++ new/ntp.conf	2017-01-17 12:02:11.968426337 -0600
@@ -1,16 +1,44 @@
-# This is the most basic ntp configuration file
 # The driftfile must remain in a place specific to this
 # machine - it records the machine specific clock error
-driftfile /etc/ntp.drift
+# Driftfile must be in a directory owned by ntp
+driftfile /var/lib/ntp/ntp.drift
+
+# The following code is for evaluating the timeserver.
+# Remove the # to activate the statistics
+# statistics loopstats
+# statistics peerstats
+# statsdir /var/log/ntpstats
+# filegen peerstats file peerstats type day link enable
+# filegen loopstats file loopstats type day link enable
+
+# This is the US timeserver pool.  You should use a pool
+# close to your location.
+#pool us.pool.ntp.org iburst
+
 # This should be a server that is close (in IP terms)
 # to the machine.  Add other servers as required.
-# Unless you un-comment the line below ntpd will sync
-# only against the local system clock.
 #
 # server time.server.example.com
 #
+
+restrict default kod nomodify notrap nopeer noquery
+restrict -6 default kod nomodify notrap nopeer noquery
+restrict 127.0.0.1 mask 255.255.255.0
+restrict -6 ::1
+
+# GPS Serial data reference (NTP0)
+# This sets the GPS 50 milliseconds slower than the PPS.
+server 127.127.28.0
+fudge 127.127.28.0 time1 0.050 refid GPS
+
+# GPS PPS reference (NTP2)
+server 127.127.28.2 prefer
+fudge 127.127.28.2 time1 0.000 refid PPS
+
 # Using local hardware clock as fallback
 # Disable this when using ntpd -q -g -x as ntpdate or it will sync to itself
+# The stratum should be a high value so this does not get chosen
+# except in dire circumstances.
 server 127.127.1.0
 fudge 127.127.1.0 stratum 14
 # Defining a default security setting