[ntp:questions] NTP Sync Issues

Adam Johnson a.johnson at wintoncapital.com
Fri Jun 6 10:41:39 UTC 2008


We have 3 sites and we are experiencing some strange problems in one of
the sites. We use NTP to keep the servers in time and this works fine
for 2 of the sites but in one of the site we get these errors in the log

ntpd[30062]: synchronized to server, stratum 3
ntpd[30062]: no servers reachable
ntpd[30062]: synchronized to server, stratum 3
ntpd[30062]: time reset +2.119167 s
ntpd[30062]: synchronized to server, stratum 3

For some reason the servers in that site seems to drop back between 2
and 3 seconds behind the other sites for no apparent reason. Both the
other sites work without any problem. We have run a packet capture at a
working site and at the site with the problems and we dont see any
differences other than the server becoming unsychronized frequently. We
have checked the main firewall and that is not blocking access and the
local firewalls are disabled. All our sites are connected via a
dedicated link and I have tried connecting to ntp servers in the other
sites and the problem persists. It looks like something local keeps
changing the time but I can figure out what.

 

The ntp.conf is the same for all sites except the servers are different.
I have tried using burst and iburst but that hasnt worked.

 

# Permit time synchronization with our time source, but do not

# permit the source to query or modify the service on this system.

restrict default kod nomodify notrap nopeer noquery

restrict -6 default kod nomodify notrap nopeer noquery

 

# Permit all access over the loopback interface.  This could

# be tightened as well, but to do so would effect some of

# the administrative functions.

restrict 127.0.0.1

restrict -6 ::1

 

server ipAddres iburst

restrict networkAddress mask networkMask

server ipAddres iburst

restrict networkAddress mask networkMask

 

driftfile /var/lib/ntp/drift


Any help would be greatly appreciated.

Thanks

 




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