NTP is wrong by almost 3 minutes.

pfBasic

I've noticed that my NTP is wrong recently, by a lot, nearly 3 minutes.

I've tried using the pfsense pool NTP servers and the NIST servers. I'm comparing the time from pfsense to the time on both my cell phone, and also the times when I go to the NIST website, and the US Navy time website. NIST, US Navy, and my cell phone all agree, and my pfsense box and desktop (connected to pfsense) both agree, but pfsense is almost three minutes faster than the US Navy, NIST & my cellphone.

I've tried restarting the service, just form looking at the RRD graphs is appears that the statistics have tightened up somewhat over the last month.

Any suggestions?

johnpoz

So what does pfsense show for its status on its ntp?

status, ntp - should show you what pfsense is using. Does it show reach of 377? Post up this screenshot.

Keep in mind ntp doesn't instantly change a devices clock. It adjusts the time of the device to sync up with its timesource and once in sync to stay there. If you graphing ntp stuff - lets look at just what its reporting for offset for a say the last day.. You can undo all the other stuff and just look at the offset.. You can see if its getting closer or just all over the board, etc..

ntp.jpg_thumb

pfBasic

OK thanks, here are the graphs and status. I'm also looking at the NTP widget on my pfsense dashboard, it does match up with my desktop clock and they have been for well over 24 hours since I first noticed this.

01.jpg_thumb

02.jpg_thumb

johnpoz

Other than not having 377 on your active server.. That all looks up and up.. Means your dropping packets to that server.. Also that your poll time is higher then your 256 setting.. Would point to having trouble talking to that server.

376 points to you have dropped the last packet, you will see reach cycle down to 177 until that no answer cycles through the 8 bit buffer..

So your saying this time is 3 minutes off?? Your ref ID is nist and your syncing off a stratum 1.. I find it very unlikely that time is off by 3 minutes from these servers.. Your currently showing offset of .033 millisecons.. or .000033 Seconds..

Where are you think pfsense time is off? The web gui status page? The time shown there??

edit: One thing I would suggest is you find some closer servers to sync off of.. Your delay is 70 some ms.. Look here for stratum 1's that are closer to you.. Find something in your state or region, etc.

http://support.ntp.org/bin/view/Servers/StratumOneTimeServers

Pay attention to their rules - some don't like to be queried unless your providing time for large number of clients, etc. There is also the stratum 2 list
http://support.ntp.org/bin/view/Servers/StratumTwoTimeServers

Which are also fine to use..

pfBasic

Well this is what I noticed. I actually noticed it because my desktops time was off from my cellphones time, so then I went into pfsense and compared pfsense time to government time servers.

Maybe this isn't a valid comparison, but I don't see why this much of a difference would be showing?

01.jpg_thumb

johnpoz

is your ntp widget counting.. Or is it stuck there?

I just added the widget, and then called up that nist page in another window and put them side by side and they show exact same time

I assume that page is pulling time from the ntp server and pfsense time.. But its a browser thing - maybe its pulling time from your local machine? Clearly what you posted is that the time is insync with its source only off by a few ms..

Off the top not sure would could account for the difference other than browser stuck not refreshing, etc.?

If you want to do a live check to see if pfsense clock is off you could use ntpdate in test mode with the -d and point it to the IP of any ntp server you want to check it against

example


[2.3.2-RELEASE][root@pfsense.local.lan]/root: ntpdate -d 192.168.9.32
21 Dec 14:06:02 ntpdate[45505]: ntpdate 4.2.8p8@1.3265-o Fri Jun 10 15:40:54 UTC 2016 (1)
transmit(192.168.9.32)
receive(192.168.9.32)
transmit(192.168.9.32)
receive(192.168.9.32)
transmit(192.168.9.32)
receive(192.168.9.32)
transmit(192.168.9.32)
receive(192.168.9.32)
server 192.168.9.32, port 123
stratum 1, precision -20, leap 00, trust 000
refid [PPS], delay 0.02609, dispersion 0.00006
transmitted 4, in filter 4
reference time:    dc055f21.f87dc034  Wed, Dec 21 2016 14:05:53.970
originate timestamp: dc055f30.d2941d7d  Wed, Dec 21 2016 14:06:08.822
transmit timestamp:  dc055f30.d28388c7  Wed, Dec 21 2016 14:06:08.822
filter delay:  0.02675  0.02632  0.02617  0.02609
         0.00000  0.00000  0.00000  0.00000
filter offset: -0.00018 -0.00018 -0.00009 -0.00007
         0.000000 0.000000 0.000000 0.000000
delay 0.02609, dispersion 0.00006
offset -0.000070

21 Dec 14:06:08 ntpdate[45505]: adjust time server 192.168.9.32 offset -0.000070 sec
[2.3.2-RELEASE][root@pfsense.local.lan]/root:

21 Dec 14:06:08 ntpdate[45505]: adjust time server 192.168.9.32 offset -0.000070 sec

so you see there my pfsense says its off by 70 us from my ntp server..

timediff.jpg_thumb

pfBasic

ok thanks ill run that check, and no it isn't stuck, all three of the times pulled up in webpages on that screenshot were counting seconds.

pfBasic

I ran ti twice, here is the output, I noticed at the end of the first run, after it gives me the offset time it says "325 sec", whats taht about?

ntpdate -d time.nist.gov
21 Dec 12:27:10 ntpdate[90838]: ntpdate 4.2.8p8@1.3265-o Tue Jul 19 16:25:10 UTC                                                                                                                                                              2016 (1)
transmit(128.138.141.172)
receive(128.138.141.172)
transmit(128.138.141.172)
receive(128.138.141.172)
transmit(128.138.141.172)
receive(128.138.141.172)
transmit(128.138.141.172)
receive(128.138.141.172)
server 128.138.141.172, port 123
stratum 1, precision -29, leap 00, trust 000
refid [NIST], delay 0.09991, dispersion 0.00021
transmitted 4, in filter 4
reference time:    dc0563c9.00000000  Wed, Dec 21 2016 12:25:45.000
originate timestamp: dc056424.63b52a21  Wed, Dec 21 2016 12:27:16.389
transmit timestamp:  dc056424.5befb402  Wed, Dec 21 2016 12:27:16.359
filter delay:  0.09991  0.09993  0.10071  0.10135
         0.00000  0.00000  0.00000  0.00000
filter offset: -0.00832 -0.00838 -0.00796 -0.00751
         0.000000 0.000000 0.000000 0.000000
delay 0.09991, dispersion 0.00021
offset -0.008325

21 Dec 12:27:16 ntpdate[90838]: adjust time server 128.138.141.172 offset -0.008   sec  325 sec  
```

ntpdate -d time.nist.gov
21 Dec 12:32:39 ntpdate[16340]: ntpdate 4.2.8p8@1.3265-o Tue Jul 19 16:25:10 UTC 2016 (1)
transmit(129.6.15.30)
receive(129.6.15.30)
transmit(129.6.15.30)
transmit(129.6.15.30)
receive(129.6.15.30)
transmit(129.6.15.30)
transmit(129.6.15.30)
server 129.6.15.30, port 123
stratum 1, precision -29, leap 00, trust 000
refid [ACTS], delay 0.15990, dispersion 24.00020
transmitted 4, in filter 4
reference time: dc056561.1ebacc2a Wed, Dec 21 2016 12:32:33.120
originate timestamp: dc05656b.6a52fae8 Wed, Dec 21 2016 12:32:43.415
transmit timestamp: dc05656d.512dbb90 Wed, Dec 21 2016 12:32:45.317
filter delay: 0.15997 0.00000 0.15990 0.00000
0.00000 0.00000 0.00000 0.00000
filter offset: 0.030677 0.000000 0.031073 0.000000
0.000000 0.000000 0.000000 0.000000
delay 0.15990, dispersion 24.00020
offset 0.031073

21 Dec 12:32:47 ntpdate[16340]: adjust time server 129.6.15.30 offset 0.031073 s ec

johnpoz

Not sure, don't think ever seen anything like that before.

You can see it sends 4 queries, and shows your offset from all 4 off them

filter offset: -0.00832 -0.00838 -0.00796 -0.00751

So not sure where that odd 325 display would come from??

pfBasic

Any guesses as to why I am seeing such a big difference?

KOM

Grasping at straws, but is the hardware clock on the unit itself correct?

pfBasic

I dont know, how could I check that?

KOM

If it's a PC of some type then I would look in the BIOS. If it's something else then I don't know.

dennypage

I hate to ask stupid questions, but there are some basics…

1. Ignoring the NTP widget for the moment, what is shown as the current date/time in the System Information widget? Does it agree or disagree with www.time.gov?

2. Have you cleared your browser's cache?

w0w

To eliminate all possible browser cache problems just go to Diagnostics ->Command Prompt
type "date" without quotes and wait for the answer.
Or do the same in shell…

I don't think it's related to any cache just because in logs we already have

"21 Dec 12:27:16 ntpdate[90838]: adjust time server 128.138.141.172 offset -0.008 sec 325 sec"

To check what hardware clocks you have run
dmesg | grep timer

and/or

sysctl kern.timecounter

You should see all possible timers and counters found and/or used by system. You can also change it to desired, tuning kern.timecounter.hardware.
Read https://www.freebsd.org/doc/en/books/faq/troubleshoot.html

pfBasic

Thanks all, the System Information Widget was also wrong.

w0w's suggestion seems to have fixed system time.

: dmesg | grep Timecounter
Timecounter "i8254" frequency 1193182 Hz quality 0
Timecounter "HPET" frequency 14318180 Hz quality 950
Timecounter "ACPI-fast" frequency 3579545 Hz quality 900
Timecounters tick every 1.000 msec
Timecounter "TSC-low" frequency 1546529202 Hz quality 1000

: sysctl kern.timecounter.hardware=HPET
kern.timecounter.hardware: TSC-low -> HPET

So now System time matches time.gov, however NTP time remains the same although I don't know if this will fix itself given a little time? I restarted the service but the NTP offset remains the same.

AR15USR

I'm seeing the same issue with the NTP time being off by 5mins. Never noticed that till now. My system clock matches the NIST time though.

Running 'date' from the command prompt returns the system time which is correct to the NIST time. The NTP widget is 5 mins off

AR15USR

I just polled the ntp server pool I'm using (pool.ntp.org) and it is off by the same 5 mins.

sntp 0.pool.ntp.org

When I poll nist it shows the same 5 minute discrepancy

sntp 128.138.141.172

AR15USR

If anyone is interested I switched my ntp servers from ntp.org to the NIST servers and the discrepancy has resolved itself..

pfBasic

That is interesting.

I have been using time.nist.gov for a few days now and my NTP time is still off by a few minutes. System time now matches up but NTP has not resolved itself, I restarted the service over a day ago and it is still off by a few minutes.

Anyone know what the root problem is here, especially now that I am apparently not the only one seeing some issues with time?