Sample config for peering multicast NTP servers

multicast.ntp.conf

# /etc/ntp.conf for multicast servers
# Kenneth Finnegan, 2014


# Logging of stats, etc
driftfile /var/lib/ntp/ntp.drift
statsdir /var/log/ntpstats/
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

# Pull multiple ntp.org pool NTP servers as the basis for local time
server 0.ubuntu.pool.ntp.org
server 1.ubuntu.pool.ntp.org
server 2.ubuntu.pool.ntp.org
server 3.ubuntu.pool.ntp.org

# Access control configuration
# For multicast, MAKE SURE TO REMOVE nopeer
restrict -4 default kod notrap nomodify noquery
restrict -6 default kod notrap nomodify noquery

# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1

# Beacon to this locally admin address
# Note that ttl is an index into the ttl array, not an actual ttl value
# By default, it seems to be 0, which maps to 1, which doesn't cross subnets
# ttl 7 sets it to the maximum value of 224, since the default array is multiples of 32
broadcast 239.192.1.1 ttl 7

# Disable authentication and listen for the other peer servers
disable auth
multicastclient 239.192.1.1

ntpq_output.txt

kenneth@KWF3:~$ ntpq -pn -c rv
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
-10.44.1.1       132.163.4.102    3 u  521 1024  377    0.302   -9.587   5.805
-198.199.111.124 216.218.192.202  2 u   34 1024  377   24.987   13.977   1.416
*166.70.136.41   .GPS.            1 u  773 1024  377   77.533   -5.500   3.148
-2001:4f8:fff7:1 216.218.254.202  2 u 1014 1024  377   24.295   11.447   1.555
+64.246.132.14   .CDMA.           1 u  253 1024  377   97.612    9.846   0.523
+91.189.89.199   193.79.237.14    2 u   52 1024  377  152.725    8.163   1.508
 239.192.1.1     .MCST.          16 u    -   64    0    0.000    0.000   0.002
-10.44.1.188     10.44.1.13       3 m   19   64  376    0.760   -4.619   0.013
-10.44.1.142     10.44.1.13       3 m   23   64  377    0.092   -4.532   0.044

associd=0 status=0615 leap_none, sync_ntp, 1 event, clock_sync,
version="ntpd 4.2.6p3@1.2290-o Tue Jun  5 20:12:08 UTC 2012 (1)",
processor="x86_64", system="Linux/3.2.0-58-generic", leap=00, stratum=2,
precision=-19, rootdelay=77.533, rootdisp=47.586, refid=166.70.136.41,
reftime=d67d7a9a.b7d316b7  Sun, Jan 12 2014 12:33:30.718,
clock=d67d7d9f.b5ac8204  Sun, Jan 12 2014 12:46:23.709, peer=36371,
tc=10, mintc=3, offset=2.949, frequency=-56.460, sys_jitter=12.017,
clk_jitter=1.622, clk_wander=0.241