It seems the firewall blocking UDP 123
Main Topics
Browse All TopicsThe following instructions were set on the router
clock timezone GMT -4
ntp server 129.6.15.28
But the sh ntp status saids that the clock is unsynchronized.
CORE1#sh ntp assoc
address ref clock st when poll reach delay offset disp
~129.6.15.28 0.0.0.0 16 - 64 0 0.0 0.00 16000.
* master (synced), # master (unsynced), + selected, - candidate, ~ configured
CORE1#
CORE1#
CORE1#sh ntp status
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is 2**18
reference time is 00000000.00000000 (20:00:00.000 GMT Thu Dec 31 1899)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.00 msec, peer dispersion is 0.00 msec
CORE1#
What I'm doing wrong?
This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.
Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.
If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.
Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.
Access the answers to your technology questions today.
30-day free trial. Register in 60 seconds.
Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Try it out and discover for yourself.
30-day free trial. Register in 60 seconds.
Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.
Well,
While waiting for the sec-admin to take action, I took another route and decide to use other of the internal routers that has access to the Internet as a ntp server, using the ntp master command. This time the clock was synchronized. So it seems that you were right about udp 123 being blocked by the firewall. No other parameters in the configuration are affecting the time synchronization.
Business Accounts
Answer for Membership
by: wiscomPosted on 2009-08-20 at 07:44:49ID: 25143155
Hi,
Ping from CORE1 to the NTP server.
If you got a reply see if there are filters in the path which are blocking UDP port 123
A/