Sample ntp.conf with whitelisting by host/network

ntp.conf

riftfile        /var/lib/ntp/ntp.drift
statsdir /var/log/ntpstats/

restrict	default	ignore

restrict        127.0.0.1
restrict        127.127.1.0
restrict -6     ::1

# You only want to allow a class 24 and two specific hosts to query your server for time
# These are 1.2.3.0/24, 4.5.6.7/32, 6.7.8.9/32
restrict -4     1.2.3.0	mask	255.255.255.0
restrict -4     4.5.6.7	mask	255.255.255.255
restrict -4     6.7.8.9	mask	255.255.255.255 

server          0.pool.ntp.org	iburst nomodify notrap nopeer noquery
restrict	0.pool.ntp.org	iburst nomodify notrap nopeer noquery
server          1.pool.ntp.org	iburst nomodify notrap nopeer noquery
server          2.pool.ntp.org	iburst nomodify notrap nopeer noquery

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable