Issues with NTP on Pi 3

Product support balenaOS
1

Hi all, I have a Pi 3 running OS 2.50.4 and am having problems with getting a correct system time. When I run date on the command line I get the 9th of June (today is the 17th). I thought it may have failed to sync time with an NTP server so I rebooted, but with the same issues.

I suspected that the NTP services may be getting blocked by the firewall sat on the network this unit is installed into, so I asked the on-site IT team to open up port 123 UDP as per the docs however I’m still seeing the same issues.

Running chronyc sources both before the firewall rule and after shows the following (in other words, it still can’t reach the NTP servers):

210 Number of sources = 4
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^? time.cloudflare.com           0  14     0     -     +0ns[   +0ns] +/-    0ns
^? 183.ip-51-89-151.eu           0  14     0     -     +0ns[   +0ns] +/-    0ns
^? ntp1.doorhan.ru               0  14     0     -     +0ns[   +0ns] +/-    0ns
^? ns4.turbodns.co.uk            0  14     0     -     +0ns[   +0ns] +/-    0ns

So my question is: do you think the firewall has been updated incorrectly, thus still not allowing the requests to the NTP server through, or do you think there may be something else at play here?

Is there any way natively through balenaOS to check whether the ports have correct access?

Thanks all.

2

Hi there, it indeed sounds like a firewall issue. You can try running chronyc -a 'burst 4/4' while SSHed in the hostOS and see if the time is updated correctly. You could also try running a device on a different network just so you can check if you can reproduce the issue. Let us know how it goes, and we can investigate further if needed.

3

Hi thanks for this. So I’ve just tried running this and I get a 200 OK back - which I assume just means the command ran ok? However checking date and chronyc sources still shows issues:

root@deff851:~# chronyc -a 'burst 4/4'
200 OK
root@deff851:~# chronyc sources
210 Number of sources = 4
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^? time.cloudflare.com           0  14     0     -     +0ns[   +0ns] +/-    0ns
^? 183.ip-51-89-151.eu           0  14     0     -     +0ns[   +0ns] +/-    0ns
^? ntp1.doorhan.ru               0  14     0     -     +0ns[   +0ns] +/-    0ns
^? server1.quickdrivingtest>     0  14     0     -     +0ns[   +0ns] +/-    0ns
root@deff851:~# date           
Tue Jun  9 15:38:57 UTC 2020
root@deff851:~#
4

Hi,
it does not look like the chronyc -a 'burst 4/4'command has fixed the time and it indeed looks like you can not access the NTP servers. Could you please confirm with your IT team that the UDP port 123 is open for outgoing connections? Also, when NTP is blocked on firewall, it is usually because local servers are provided and you are expected to use those, could you please also check with your IT team whether there are some local NTP servers in place that you should use?

1 Like