[ntp:questions] Manycast Sync Issue

Potter, Timothy UTC CCS Timothy.Potter at KiddeUS.com
Wed May 3 10:55:42 UTC 2017


I am having an issue with my machines syncing while using manycast.  I have a series of 12 machines all running ntpd.  They each have 2 interface cards, eth0 and eth1.  Each interface is connected to a unique subnet.  Machine 1 is setup as the manycast server.  Its eth0 is connected to the public internet.  Its eth1 is connected to eth0 of machine 2.   Its ntpd.conf file looks like this:

#
driftfile /etc/ntp.drift
disable auth

# NTP clients will also act like a server once they sync
manycastserver ff0e::101

# Enable syncing with servers on the same stratum
tos cohort 0

# Keep alive hops for the multicast packets
ttl 4 8 16 32

# Update the realtime clock and override its default
# stratum of 0.
Server 0.pool.ntp.org
server 127.127.1.0 prefer #Real Time Clock
fudge 127.127.1.0 stratum 10




Machine 2 - 12 are all setup as manycast clients and manycast servers.  Eth1 of Machine 2 is connected to eth0 of Machine 3 and so on.  Each machine is setup to forward all ipv6 traffic and all ipv6 multicast.  The clients' ntpd.conf looks like this:

#
driftfile /etc/ntp.drift
disable auth

# NTP clients will also act like a server once they sync
manycastserver ff0e::101
manycastclient ff0e::101 iburst

# Enable syncing with servers on the same stratum.  Used for client machines
tos cohort 0

# Keep alive times for the multicast packets
ttl 4 8 16 32

# Update the realtime clock and override its default
# stratum of 0.
fudge 127.127.1.0 stratum 11


The problem I am having is the first 6 machines sync up just fine.  Machines 7 - 12 don't sync up at all.  I have replaced cables, interface cards, other hardware to rule that out.   I am thinking it must be a configuration issue.  Any thoughts?

Tim




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