[ntp:questions] sntp: rejects packets from ntpd when "disable ntp" is used

Daniel Kabs daniel.kabs at gmx.de
Mon Mar 20 09:48:40 UTC 2006

Hello there!

Some words about the context of my problem: I have several systems whose 
system clock skew I want to measure remotely (does that sound familiar 
to you :-). These systems run NTPD configured for a reliable time server 
and cunningly use the option "disable ntp" so the kernel frequency 
discipline is disabled.

The skew is the first derivative of offset with time. To read the offset 
remotely I use ntpdate. Now some people and 
https://ntp.isc.org/bin/view/Dev/DeprecatingNtpdate say, I should use 
sntp instead.

So I went ahead and compiled sntp. Running sntp against the above 
mentioned systems gives me the following error:
  Incoming packet on socket 0:
  dc0008f1 00000000 001209d0 494e4954 00000000 00000000 c7c8f4ed 1a280000
  c7c8f4ec 64275254 c7c8f4ec 6438b04a
  sta=3 ver=3 mod=4 str=0 pol=8 dis=18.038330 ref=0.000000
  ori=3351835885.102173 rec=3351835884.391225
  tra=3351835884.391490 cur=3351835885.103798
  sntp: Unusable NTP packet rejected on socket 0 (f=0, status 3, version
  3, stratum 0)

Looking at the source code of sntp, read_packet() in main.c complains 
about data->status == 3

Why is that?

Refactor, don't archive! - SamHasler - 28 Aug 2004 - twiki.org

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