NTP synchronized: no

Patrick Dupre pdupre at gmx.com
Tue Sep 8 18:30:32 UTC 2015



===========================================================================
 Patrick DUPRÉ                                 | | email: pdupre at gmx.com
 Laboratoire de Physico-Chimie de l'Atmosphère | |
 Université du Littoral-Côte d'Opale           | |
 Tel.  (33)-(0)3 28 23 76 12                   | | Fax: 03 28 65 82 44
 189A, avenue Maurice Schumann                 | | 59140 Dunkerque, France
===========================================================================


> Sent: Tuesday, September 08, 2015 at 8:27 PM
> From: "Rick Stevens" <ricks at alldigital.com>
> To: "Community support for Fedora users" <users at lists.fedoraproject.org>
> Subject: Re: NTP synchronized: no
>
> On 09/08/2015 10:52 AM, Patrick Dupre wrote:
> > Hello,
> >
> > I am not sure to understand.
> > The previous conclusion was that the firewall did not let me go through.
> > Now, I have:
> >                   :::*                                5704/chronyd
> > [root at Homere ~]# netstat -pna | grep :123
> > udp        0      0 193.49.194.196:35562    210.173.160.27:123      ESTABLISHED 5704/chronyd
> > udp        0      0 193.49.194.196:60225    210.173.160.57:123      ESTABLISHED 5704/chronyd
> > udp        0      0 193.49.194.196:36218    210.173.160.87:123      ESTABLISHED 5704/chronyd
> > udp        0      0 193.49.194.196:36803    178.32.54.53:123        ESTABLISHED 5704/chronyd
> > udp        0      0 193.49.194.196:57367    62.210.85.244:123       ESTABLISHED 5704/chronyd
> > udp        0      0 0.0.0.0:123             0.0.0.0:*                           5704/chronyd
> > udp        0      0 193.49.194.196:57601    91.121.169.20:123       ESTABLISHED 5704/chronyd
> > udp        0      0 193.49.194.196:34907    195.83.66.158:123       ESTABLISHED 5704/chronyd
> > udp6       0      0 :::123                  :::*                                5704/chronyd
> >
> > timedatectl
> >        Local time: Tue 2015-09-08 19:46:24 CEST
> >    Universal time: Tue 2015-09-08 17:46:24 UTC
> >          RTC time: Tue 2015-09-08 17:46:24
> >          Timezone: Europe/Paris (CEST, +0200)
> >       NTP enabled: yes
> > NTP synchronized: yes
> >   RTC in local TZ: no
> >        DST active: yes
> >   Last DST change: DST began at
> >                    Sun 2015-03-29 01:59:59 CET
> >                    Sun 2015-03-29 03:00:00 CEST
> >   Next DST change: DST ends (the clock jumps one hour backwards) at
> >                    Sun 2015-10-25 02:59:59 CEST
> >                    Sun 2015-10-25 02:00:00 CET
> >
> > traceroute -p 123 -U 123.204.45.116
> > traceroute to 123.204.45.116 (123.204.45.116), 30 hops max, 60 byte packets
> >   1  cisco-dk.univ-littoral.fr (193.49.194.1)  1.768 ms  1.944 ms  2.151 ms
> >   2  192.168.168.203 (192.168.168.203)  0.317 ms  0.417 ms  0.486 ms
> >   3  * * *
> >   4  * * *
> >
> > It does not looks like that the connection with the time server is established.
> > However, it says:
> > NTP synchronized: yes
> >
> > On the other side, the machine is 10 s beyond http://www.worldtimeserver.com/
> 
> To see what chronyd is doing, run "chronyc -n sources" as the root
> user. Don't rely on what netstat is telling you.

chronyc -n sources 
210 Number of sources = 7
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^? 178.32.54.53                  0  10     0   10y     +0ns[   +0ns] +/-    0ns
^? 195.83.66.158                 0  10     0   10y     +0ns[   +0ns] +/-    0ns
^? 91.121.169.20                 0  10     0   10y     +0ns[   +0ns] +/-    0ns
^? 62.210.85.244                 0  10     0   10y     +0ns[   +0ns] +/-    0ns
^? 210.173.160.27                0  10     0   10y     +0ns[   +0ns] +/-    0ns
^? 210.173.160.57                0  10     0   10y     +0ns[   +0ns] +/-    0ns
^? 210.173.160.87                0  10     0   10y     +0ns[   +0ns] +/-    0ns



> Here's what I see:
> 
> [root at prophead ~]# chronyc -n sources
> 210 Number of sources = 4
> MS Name/IP address         Stratum Poll Reach LastRx Last sample
> ===============================================================================
> ^* 132.163.4.101                 1  10   377   316  +5458us[+5379us] +/- 
>    32ms
> ^- 104.41.150.68                 2  10   357   806  -8917us[-8979us] +/- 
>    91ms
> ^+ 192.155.90.13                 2  10   377   912    -12ms[  -12ms] +/- 
>    67ms
> ^- 198.211.106.151               2   9   377   486    -12ms[  -12ms] +/- 
>    81ms
> 
>  From the chrony docs, the first two columns ("M" and "S") mean:
> 
> 'M'
>       This indicates the mode of the source.  '^' means a server, '='
>       means a peer and '#' indicates a locally connected reference clock.
> 
> 'S'
>       This column indicates the state of the sources.  '*' indicates the
>       source to which 'chronyd' is currently synchronised.  '+' indicates
>       acceptable sources which are combined with the selected source.
>       '-' indicates acceptable sources which are excluded by the
>       combining algorithm.  '?' indicates sources to which connectivity
>       has been lost or whose packets don't pass all tests.  'x' indicates
>       a clock which 'chronyd' thinks is is a falseticker (i.e.  its time
>       is inconsistent with a majority of other sources).  '~' indicates a
>       source whose time appears to have too much variability.  The '?'
>       condition is also shown at start-up, until at least 3 samples have
>       been gathered from it.
> 
> 
> In my case, they're all servers ("M" all show "^") and I'm currently 
> sync'd to 132.163.4.101 (the "*" under "S"). The second and fourth
> servers listed are "acceptable sources" but excluded based on the
> combining algorithms. The third item is acceptable on its own.
> 
> Another useful version is "chronyc activity":
> 
> [root at prophead ~]# chronyc activity
> 200 OK
> 4 sources online
> 0 sources offline
> 0 sources doing burst (return to online)
> 0 sources doing burst (return to offline)
> 0 sources with unknown address
> 
> So I see four sources online and available.
> 
> As others have said, if you're in a university setting it is entirely
> possible that they want you to use THEIR NTP servers, not ones wild on
> the net. They may very well block UDP port 123 on their firewalls so 
> your best bet is to ask the admins which NTP servers are available to
> you.
> 
> On my corporate firewall, I block NTP for most of my users, but I have
> NTP services running on my DNS cache servers. That's what the people
> behind my firewall get access to (and what's configured to be returned
> on DHCP requests from them).
> 
> >> Sent: Tuesday, September 08, 2015 at 7:42 PM
> >> From: "John Pilkington" <J.Pilk at tesco.net>
> >> To: users at lists.fedoraproject.org
> >> Subject: Re: NTP synchronized: no
> >>
> >> On 08/09/15 18:02, Rick Stevens wrote:
> >>> On 09/08/2015 03:27 AM, John Pilkington wrote:
> >>>> On 08/09/15 10:52, Ed Greshko wrote:
> >>>>> On 09/08/15 17:29, Patrick Dupre wrote:
> >>>>>> I cannot synchronize the date:
> >>>>>> My undestanding is that it should be set by:
> >>>>>> timedatectl set-ntp yes
> >>>>>>
> >>>>>> Here, the results of some commands:
> >>>>>>
> >>>>>> netstat -a |grep ntp
> >>>>>> udp        0      0 localhost.localdo:51314 ns346276.ip-94-23-3:ntp
> >>>>>> ESTABLISHED
> >>>>>> udp        0      0 localhost.localdo:39994 tomia.ordimatic.net:ntp
> >>>>>> ESTABLISHED
> >>>>>> udp        0      0 localhost.localdo:45035 ntp.tuxfamily.net:ntp
> >>>>>> ESTABLISHED
> >>>>>> udp        0      0 localhost.localdo:49209 host3.nuagelibre.or:ntp
> >>>>>> ESTABLISHED
> >>>>>> warning, got bogus l2cap line.
> >>>>
> >>>> That looks different: here's mine.
> >>>>
> >>>> [john at HP_Box ~]$ netstat -a | grep ntp
> >>>> udp        0      0 0.0.0.0:ntp             0.0.0.0:*
> >>>> udp6       0      0 [::]:ntp                [::]:*
> >>>> [john at HP_Box ~]$ netstat -a | grep 323
> >>>> udp        0      0 localhost:323           0.0.0.0:*
> >>>> udp6       0      0 localhost:323           [::]:*
> >>>> plus a few irrelevant responses.
> >>>>
> >>>> but ...grep 123 shows nothing that looks relevant.
> >>>>
> >>>> Quoting from the faq:
> >>>>
> >>>> Perhaps you have a firewall set up in a way that blocks packets on port
> >>>> 323/udp.  You need to amend the firewall configuration in this case.
> >>>
> >>> ntp is UDP port 123 as is shown in your output. By default, netstat
> >>> will translate port numbers to services found in your /etc/services
> >>> file. If you want to verify it, try "netstat -apn | grep :123" and you
> >>> should see something on that port:
> >>>
> >>> [root at prophead ~]# netstat -pna | grep :123
> >>> ...
> >>> udp        0      0 192.168.1.50:58156      104.41.150.68:123
> >>> ESTABLISHED 841/chronyd
> >>> ...
> >>>
> >>> So you can see that chronyd is connected to 104.41.150.68 via UDP port 123.
> >>
> >> Thanks Rick.  On my system, ( which does have a working chrony setup)  I
> >> see:
> >>
> >> $ uname -a
> >> Linux HP_Box 3.10.0-229.11.1.el7.x86_64 #1 SMP Wed Aug 5 14:37:37 CDT
> >> 2015 x86_64 x86_64 x86_64 GNU/Linux
> >>
> >> [john at HP_Box ~]$ netstat -pna | grep :123
> >> (Not all processes could be identified, non-owned process info
> >>    will not be shown, you would have to be root to see it all.)
> >> udp        0      0 0.0.0.0:123             0.0.0.0:*
> >>           -
> >> udp6       0      0 :::123                  :::*
> >>           -
> >> [john at HP_Box ~]$ su
> >> Password:
> >> [root at HP_Box john]# netstat -pna | grep :123
> >> udp        0      0 0.0.0.0:123             0.0.0.0:*
> >>           692/chronyd
> >> udp6       0      0 :::123                  :::*
> >>           692/chronyd
> >> [root at HP_Box john]# netstat -pna | grep :323
> >> udp        0      0 127.0.0.1:323           0.0.0.0:*
> >>           692/chronyd
> >> udp6       0      0 ::1:323                 :::*
> >>           692/chronyd
> >> [root at HP_Box john]# exit
> >> exit
> >> [john at HP_Box ~]$
> >>
> >>
> >>
> >>
> >>
> >> --
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> 
> 
> -- 
> ----------------------------------------------------------------------
> - Rick Stevens, Systems Engineer, AllDigital    ricks at alldigital.com -
> - AIM/Skype: therps2        ICQ: 226437340           Yahoo: origrps2 -
> -                                                                    -
> -  BASIC is the Computer Science version of `Scientific Creationism' -
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