Hi Grant,

> I've been experimenting recently, in version 0.71, with connman's ability to 
> launch the NTP daemon in one-shot mode when the service state transitions to 
> online mode.
> 
> However, what I notice in practice is that when the time server is any named 
> entity (e.g. time.ubuntu.org or pool.ntp.org), the NTP daemon fails to 
> resolve the name, ntpd_intres gets forked and launched and then indefinitely 
> fails to resolve the name.
> 
> If I rework the plugin to delay NTP start up and then periodically retry 
> several times over time, I see the same results: NTP never successfully 
> resolves the name.
> 
> If I run tcpdump while connman is starting up and bringing up the service, I 
> see requests going out for wpad.<mydomain> to the name server; however, I 
> never see a resolve request going out on the wire for the time server, ever.
> 
> If I manually run the NTP daemon in one-shot mode, the name resolves 
> immediately and time is updated. If I run nslookup on the time server while 
> all these retries and failures are occurring from the instance dispatched in 
> connman, the name resolves successfully.

the wpad.<domain> DNS requests you see are for the Automatic Proxy
Discovery. Since they are ConnMan internal they actually do not rely on
Glibc or /etc/resolv.conf. They go directly to the reported DNS servers
from either static configuration or DHCP.

So what I am thinking is that we might have a small race condition here
where the built-in DNS proxy is not yet ready to answer DNS queries
properly. Can you try to run connmand with --nodnsproxy and see if this
changes at all. We could still have the problem that we do not
write /etc/resolv.conf early enough.

All in all, this assures me in my plans to move an actual Simple NTP
implementation directly into ConnMan instead of relying on any external
NTP implementation. I really think that ConnMan needs more fine grained
control over NTP. Same as we did with DHCP which worked out nicely.

Regards

Marcel


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