ReadyNAS Timesync - thousands of queries per day to timesync server

Very unlikely Netgear has fully fledged logging - if any at all - enabled for each basic code like connman (connmand).

When looking back in the thread, the indications came from some local DNS server logs. 

connmanctl> clock
Time = 1606046129
TimeUpdates = auto
Timezone = Europe/Zurich
TimezoneUpdates = auto
Timeservers = [ time-e.netgear.com, time-a.netgear.com ]

We have two time servers configured here (by default I guess). The SOA records for netgear.com does show a default TTL of 900 seconds (15 minutes). When looking into pool.ntp.org, we find a default TTL of 3600 seconds (one hour). This does tell the resolver - again implemented as part of thie connman thningie - that he must cache the query for 15 min resp. one hour - and must not query the DNS server with every new attempt....

Said that. I hate busybox, connman, .... and all this "optimized" crap.

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schumaku wrote:

Very unlikely Netgear has fully fledged logging - if any at all - enabled for each basic code like connman (connmand).

Well, as I posted above, the NTP time adjustments are in the log zip.  Nothing else is in my connman.log file.  I don't know what would be posted if there are errors.

The interval I am seeing is 1024 seconds.

StephenB the connman.log is generated from the collected Kernel log out. However, I would assume all potential issues would show up there.

root 5205 1 0 Aug04 ? 00:00:03 /usr/sbin/connmand -n -r

But then, for more details, connmand must be run different, with debug, e.g. 

/usr/sbin/connmand -d -n -r

Not enough experienced on overriding process handling and control on RNOS6. Can't be fun - as killing connmand does kill a lot more 8-/

Temporary solution:

I have inserted only 1 NTP server into the first field and deleted the others, i just used IP address of time.google.com and it works without DNS requests to my local DNS server.

Then i have tried to insert time.google.com (hostname) and deleted the others. I got DNS request for time.google.com to my local DNS server every 10 secs. Same with time.windows.com and with time-e.netgear.com and time-a.netgear.com (having only 1 NTP server at time).

I have tested all three (four) NTP servers in Windows OS and they all work great for timesync.

I have also disabled all the apps on ReadyNAS except Pi-Hole DNS server (cause i use it for DNS adresses translation and monitoring).

Still same.

Connman settings:

[global]
OfflineMode=false
Timeservers=time-e.netgear.com;time-a.netgear.com;
[Wired]
Enable=true
root@NAS:/etc/default/config/var/lib/connman#

Connmann main.cfg

[General]
AllowHostnameUpdates = false
NetworkInterfaceBlacklist = LeafNets,docker,tap,veth,zt

Conmann settings #2

[global]
OfflineMode=false
Timeservers=time.google.com;
TimeUpdates=auto
TimezoneUpdates=manual
[Wired]
Enable=true
Tethering=false

LATER:

But now i have discovered, that if i insert IP address of NTP server time.google.com and confirm, then i overwrite it with hostname time.google.com leaving other fields empty, i got only 3x2 (A + AAA) requests to my local DNS server and that's all. No more.

Then i have tried same with both netgear NTP servers. I inserted 2 of them, as IP addresses. Confirmed the dialogue. Then i have rewrited values with hostnames time-e.netgear.com and time-a.netgear.com and voila, only 3x2 (A + AAA) requests and no more.

It looks like a hack, so i would like to get a real solution for the future. Maybe it has something to do with Pi-Hole. But unfortunatelly i cant monitor local network DNS requests without Pi-Hole running.

EDIT: I have restarted ReadyNAS, everything went back to #$%^%!, every 5-10seconds DNS request of NTP server's hostname ip address.

You shouldn't post ReadyNAS log zips publicly, so I redacted that part.

I suggest that you should disable ipv6 in your NAS network settings, and see if that changes the behavior.

Hi,

I have tried to disable IPV6, without restart, then with restart of ReadyNAS unit, but behaviour is still same.

When only hostname like time.windows.com is inserted, i am having every 10s 2 requests - A and AAAA.

When i try inserting IP address of NTP server, save, then editing to hostname, save, DNS requests stop after 6(3x2) of them.

I would like to disable all the apps and watch & check DNS log. Is it possible to watch ReadyNAS DNS requests somehow then?

Moderator: Please remove all the links from my message #16 at this page. Thanks

This is what happens every 10 seconds on my DNS server Pi-Hole, with 1 (local) DNS server setup and 1 NTP server setup

Nov 24 18:55:53 dnsmasq[19136]: query[A] time.google.com from 192.168.1.4
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 216.239.35.0
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 216.239.35.8
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 216.239.35.4
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 216.239.35.12
Nov 24 18:55:53 dnsmasq[19136]: query[AAAA] time.google.com from 192.168.1.4
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 2001:4860:4806:4::
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 2001:4860:4806:8::
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 2001:4860:4806::
Nov 24 18:55:53 dnsmasq[19136]: cached time.google.com is 2001:4860:4806:c::

This is connmann.log

Nov 24 16:56:44 NAS connmand[2585]: ntp: adjust (slew): -0.000380 sec
Nov 24 16:57:48 NAS connmand[2585]: ntp: adjust (slew): -0.000607 sec
Nov 24 16:59:56 NAS connmand[2585]: ntp: adjust (slew): -0.000295 sec
Nov 24 17:04:13 NAS connmand[2585]: ntp: adjust (slew): -0.000316 sec
Nov 24 17:12:46 NAS connmand[2585]: ntp: adjust (slew): -0.000938 sec
Nov 24 17:29:51 NAS connmand[2585]: ntp: adjust (slew): -0.001276 sec
Nov 24 17:46:56 NAS connmand[2585]: ntp: adjust (slew): -0.002590 sec
Nov 24 18:04:01 NAS connmand[2585]: ntp: adjust (slew): +0.001719 sec
Nov 24 18:21:06 NAS connmand[2585]: ntp: adjust (slew): +0.002422 sec
Nov 24 18:38:11 NAS connmand[2585]: ntp: adjust (slew): +0.002185 sec
Nov 24 18:44:58 NAS connmand[2585]: ntp: adjust (slew): +0.000719 sec

Connmann.log looks normal to me. But i am getting mad number of DNS requests to my local DNS server for NTP server's hostname to ip address translation.

One more question. Does ReadyNAS store NTP hostname's resolved ip address in hosts file? There is no such a thing in all the hosts files on my ReadyNAS.

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Retired_Member wrote:

One more question. Does ReadyNAS store NTP hostname's resolved ip address in hosts file? 

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No.  And I don't think it should.  One aspect is that the IP address can change (especially if you are using pool.ntp.org).

But if you wanted to do that, you could manually create hosts entries for them.

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schumaku wrote:
No. A resolver does not use the hosts file for caching.

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Agreed.  If the name is in the hosts file, the ReadyNAS (like most systems) will just use the IP address in the hosts entry, and not use the various resolver services at all.

Ok, thanks for answer. I will try disable Pi-Hole and watch DNS requests from ReadyNas using some Windows DNS server.

Today (18 hours) i have around 16k requests on my DNS server for hostname time.google.com translation to IP address.

In my opinion its much easier for edit purposes, to edit NTP server IP address in GUI than editing hosts file when needed.

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Retired_Member wrote:

In my opinion its much easier for edit purposes, to edit NTP server IP address in GUI than editing hosts file when needed.

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This does offload your DNS infrastructure, but won't change anything about the cause of the short interval. Out of sight, out of mind?

Yes. But i would like to solve the problem using legit way. Inserting just IP as NTP server's address is the latest option for me.

Currently i am running some DNS server on Windows called Simple DNS Plus and i have assigned this DNS server for ReadyNAS.

It works when I try to search update of ReadyNAS OS. It works, when i try to synchronize time using default netgear NTP servers.

But i am not seeing any more requests during last 30 minutes.. connmann.log says time was synchronized twice during this period.

Is there some DNS cache that is ReadyNAS using? Because i have deleted DNS server cache and log and no more requests appeared in Simple DNS Plus server on Windows.

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Retired_Member wrote:

 

Is there some DNS cache that is ReadyNAS using?

I don't believe so.  systemd-resolve, ncsd, dnsmasq are not running on my ReadyNAS.