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Date:      Wed, 26 Feb 2020 16:37:43 +1100
From:      Dewayne Geraghty <dewaynegeraghty@gmail.com>
To:        freebsd-stable stable <freebsd-stable@freebsd.org>
Subject:   ntp problems stratum 2 to 14?
Message-ID:  <CAGnMC6q2V6tfA%2BbkSXVgTq1poaLgrkv4Hd=R6fNBAZASUZPu4A@mail.gmail.com>

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I usually run ntpd with both aslr and as user ntpd.  While testing I
noticed that my server with a direct network cable to my main time keeper,
jumped from the expected stratum 2 to 14 as follows (I record the date so I
can synch with the debug log, also below):

vm.loadavg={ 0.09 0.10 0.18 }

Wed 26 Feb 2020 15:16:38 AEDT
     remote           refid      st t when poll reach   delay   offset
 jitter
==============================================================================
 10.0.7.6        203.35.83.242    2 u   44   64  377    0.147  -227.12
 33.560
*127.127.1.1     .LOCL.          14 l   59  128  377    0.000    0.000
0.000
Wed 26 Feb 2020 15:18:46 AEDT
     remote           refid      st t when poll reach   delay   offset
 jitter
==============================================================================
 10.0.7.6        LOCAL(1)        14 u   42   64  377    0.147  -227.12
 44.529
*127.127.1.1     .LOCL.          14 l   59  128  377    0.000    0.000
0.000
Wed 26 Feb 2020 15:20:54 AEDT
     remote           refid      st t when poll reach   delay   offset
 jitter
==============================================================================
 10.0.7.6        LOCAL(1)        14 u   42   64  377    0.147  -227.12
 73.969
*127.127.1.1     .LOCL.          14 l   59  128  377    0.000    0.000
0.000
Wed 26 Feb 2020 15:23:02 AEDT
     remote           refid      st t when poll reach   delay   offset
 jitter
==============================================================================
*10.0.7.6        LOCAL(1)        14 u   37   64  377    0.164  -370.64
 74.119
 127.127.1.1     .LOCL.          14 l   59  128  377    0.000    0.000
0.000
Time marches on
Wed 26 Feb 2020 16:03:35 AEDT
     remote           refid      st t when poll reach   delay   offset
 jitter
==============================================================================
*10.0.7.6        LOCAL(1)        14 u   11   64  177    0.133   -3.148
 72.295
 127.127.1.1     .LOCL.          14 l  406  128   10    0.000    0.000
0.000
Wed 26 Feb 2020 16:05:43 AEDT
     remote           refid      st t when poll reach   delay   offset
 jitter
==============================================================================
*10.0.7.6        203.35.83.242    2 u    7   64  377    0.164  -42.789
 73.762
 127.127.1.1     .LOCL.          14 l  534  128   20    0.000    0.000
0.000

The debug for the above is:
26 Feb 14:58:33 ntpd[8772]: Command line: /usr/local/sbin/ntpd -c
/etc/ntp.conf -g -g -u ntpd --nofork
...
26 Feb 14:58:34 ntpd[8772]: 10.0.7.6 e014 84 reachable
26 Feb 14:58:35 ntpd[8772]: LOCAL(1) 8014 84 reachable
26 Feb 15:03:40 ntpd[8772]: LOCAL(1) 901a 8a sys_peer <== bad
26 Feb 15:03:40 ntpd[8772]: 0.0.0.0 c515 05 clock_sync
26 Feb 15:22:25 ntpd[8772]: 10.0.7.6 f01a 8a sys_peer  <=== Good!
26 Feb 15:22:25 ntpd[8772]: 0.0.0.0 0613 03 spike_detect -0.370644 s
26 Feb 15:30:03 ntpd[8772]: 0.0.0.0 061c 0c clock_step -0.536289 s
26 Feb 15:30:02 ntpd[8772]: 0.0.0.0 0615 05 clock_sync
26 Feb 15:30:03 ntpd[8772]: 0.0.0.0 c618 08 no_sys_peer
26 Feb 15:30:03 ntpd[8772]: 10.0.7.6 e014 84 reachable
26 Feb 15:30:07 ntpd[8772]: LOCAL(1) 8014 84 reachable
26 Feb 15:30:21 ntpd[8772]: 10.0.7.6 f01a 8a sys_peer
...
26 Feb 15:46:49 ntpd[8772]: 0.0.0.0 c618 08 no_sys_peer
26 Feb 15:46:57 ntpd[8772]: 10.0.7.6 f01a 8a sys_peer

...
26 Feb 15:56:58 ntpd[8772]: 10.0.7.6 f01a 8a sys_peer
...
26 Feb 16:24:33 ntpd[8772]: LOCAL(1) 901a 8a sys_peer <== and stays LOCAL
which is now normal for this box  :(

Should the jump to stratum 14 be expected?  Anything obviously wrong with
the ntp.conf?

I've had a few days of testing on what is usually a very stable (time-wise
system), seems that running at prio 20 is required.

/etc/ntp.conf contains
rlimit memlock -1
rlimit filenum 32
driftfile /var/db/ntp/drift
disable bclient
server 10.0.7.6 iburst minpoll 4 maxpoll 6 version 4 key 23057 prefer

server 127.127.1.1 minpoll 7 maxpoll 7
fudge  127.127.1.1 stratum 14

restrict -4 default ignore
restrict -6 default ignore
restrict 127.0.0.1  nomodify nopeer notrap
restrict -6 ::1     nomodify nopeer notrap
restrict 0.0.0.0 ignore

restrict 10.0.7.6 nomodify nopeer noquery notrap ntpport
restrict 10.169.168.91 mask 255.255.255.0 nomodify nopeer noquery notrap
ntpport kod limited


I'm also very surprised that the jitter on the server (under testing) is so
poor.  The internet facing time server is
*x.y.z.t   .ATOM.           1 u   73  512    7   23.776   34.905  95.961
but its very old and not running aslr.

Any ideas or pointers would be appreciated.  This is very, time consuming.
:)

I'm using the following command sequence as these are all being changed
sysctl kern.elf64.aslr.enable=1 kern.elf64.aslr.stack_gap=1
security.mac.ntpd.enabled=1 && \
/usr/bin/proccontrol -m aslr -s disable /usr/local/sbin/ntpdate -v -a
23057  -k /etc/ntp.keys 10.0.7.6 && sleep 2 && \
/rescue/nice -n -20  /usr/bin/proccontrol -m aslr -s disable
 /usr/local/sbin/ntpd -c /etc/ntp.conf -g -g  -u ntpd --nofork

I get similar results with /usr/sbin/ntpd, I've been testing both and
happened to record details for the port ntpd.

Regards, Dewayne



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