[ntp:questions] How common is LI=3 (clocks not synchronized)?

Robert Scott no-one at notreal.invalid
Fri Feb 3 03:15:09 UTC 2017


I am writing some parsing code for reading Time Server packets.  The
first 32 bits of the returned packet are:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|LI | VN  |Mode |    Stratum    |     Poll      |   Precision    |   
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   

When the two LI bits come back as 11 (clocks not synchronized) I have
been treating that as a fatal error for that server.  I ignore that
packet and do not attempt to retry my query for that server.  However
I have found that LI=11 is not all that uncommon for servers from the
pool.  Is my response to LI=11 the correct one?  Should I discard the
response and should I write off that server for retries?  So far, the
only reason I might retry a server is if my recvfrom() socket call
times out.

-Robert Scott
 Hopkins, MN



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