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karobar
Asked: 2018-01-11 12:37:31 +0800 CST

Is my NTP configuration working (with a multicast peer)?

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Introduction

I'm trying to do some work in which I must receive an NTP update from peers but I'm concerned that there isn't any being received. Here's the output of ntpq -np:

     remote           refid      st t when poll reach   delay   offset jitter  
==========================================================================
     239.0.1.1       .MCST.          16 u    -   64    0    0.000    0.000   0.000

Does the fact that the reach, delay, offset are all zeroes means that this host hasn't received any information from peers?

Details

I've also done ntpq, with command associations and received the following:

ind assid status  conf reach auth condition  last_event cnt
===========================================================
  1 12097  c811   yes  none   yes    reject    mobilize  1

Here's my ntp.conf:

driftfile /var/lib/ntp/drift
restrict default kod nomodify notrap nopeer noquery
restrict 127.0.0.1

statsdir /var/log/ntpstats/
logfile /var/log/ntpstats/ntpd.log

tos orphan 4
broadcast 239.0.1.1 key 1 ttl 1        # multicast server
multicastclient 239.0.1.1              # multicast client

keys /etc/ntp/keys
trustedkey 1

Here's the output log at /var/log/ntpstats/ntpd.log:

 2 Jan 16:19:57 ntpd[3554]: ntp_io: estimated max descriptors: 1024, initial socket boundary: 16
 2 Jan 16:19:57 ntpd[3554]: Listen and drop on 0 v4wildcard 0.0.0.0 UDP 123
 2 Jan 16:19:57 ntpd[3554]: Listen normally on 1 lo 127.0.0.1 UDP 123
 2 Jan 16:19:57 ntpd[3554]: Listen normally on 2 eth0.10 10.3.1.2 UDP 123
 2 Jan 16:19:57 ntpd[3554]: Listen normally on 3 eth0.172 172.20.20.2 UDP 123
 2 Jan 16:19:57 ntpd[3554]: Listening on routing socket on fd #20 for interface updates
 2 Jan 16:19:57 ntpd[3554]: Listen normally on 4 multicast 239.0.1.1 UDP 123
 2 Jan 16:19:57 ntpd[3554]: Joined 239.0.1.1 socket to multicast group 239.0.1.1
 2 Jan 16:19:57 ntpd[3554]: 0.0.0.0 c016 06 restart
 2 Jan 16:19:57 ntpd[3554]: 0.0.0.0 c012 02 freq_set kernel 0.000 PPM
 2 Jan 16:19:57 ntpd[3554]: 0.0.0.0 c011 01 freq_not_set
 2 Jan 16:19:58 ntpd[3554]: io_setbclient: Opened broadcast client on interface #3 eth0.172
 2 Jan 16:19:58 ntpd[3554]: io_setbclient: Opened broadcast client on interface #2 eth0.10
 2 Jan 16:30:35 ntpd[3554]: 0.0.0.0 0614 04 freq_mode

Questions

Question 1

Is my NTP configuration receiving updates? If not, how can it be fixed?

Question 2 (Supplemental/Optional)

From what I understand, a multicast peer indicates that any host in the multicast group can send and receive NTP information from any other host, is this accurate?

Question 3 (Supplemental/Optional)

What do the last 6 lines of the log indicate (alternatively, where can I find documentation which explains)? Of particular interest to me is the following:

0.0.0.0 c012 02 freq_set kernel 0.000 PPM

I don't really understand any part of this. Does 0.0.0.0 indicate some peer behind the multicast address? What does c012 and 02 mean? Isn't this setting the drift time (the clock drifts 0 seconds over 0 seconds)?

ntp

0 Answers