NTP time issue with md5 authentication.

UNIX for Advanced & Expert Users
1

Hi All

Appreciate your help.

Here is the scenario:

  1. Five months back we configured md5 authentication with network devices and NTP server and it worked fine.
    2.Last week all of a sudden the network devices are out of sync.
    3.We changed the md5 key and it started working.

Questions:
1.Why it failed to work after a long time?
2.With new key it's working but the main problem is we need to configure all the network devices ( around 200 devices) again.
3.Although the network devices are out of sync the NTP device was showing they are sync. Please find below output for the two network devices.

Please let me know if you need more information.

NTP SERVER:~)-> ntpdc -c monlist | grep  X.X.X.X
X.X.X.X               123 X.X.X.X       1721 3 4     d4     31      27

NTP SERVER:~)-> ntpdc -c monlist | grep  X.X.X.X
X.X.X.X              123 X.X.X.X        834 3 2     d4     65      49