On Tue, Nov 28, 2023 at 04:19:07PM +0100, Paul de Weerd wrote:
> Hi all,
>
> I have a few APU's I'm using to experiment with some stuff. I found all
> of them unable to sync with NTP because they don't have IPv4
> connectivity to the outside world.
>
> Digging a bit deeper, it turns out that v6 is only configured after
> ntpd is started. This means the constraints cannot be reached (ntpd
> logs "constraints configured but none available"). Even if v6 becomes
> available (shortly after) ntpd is started, ntpd still refuses to try
> to connect to the constraints over IPv6.
>
> Simply restarting ntpd when an IPv6 address is configured makes
> everything go again: the constraint servers can be reached, so those
> are checked, and then the regular NTP servers also work fine.
>
> Address configuration is dynamic:
>
> --- cat /etc/hostname.em0 --------------------------------------------
> up
> inet autoconf
> inet6 autoconf
> ----------------------------------------------------------------------
>
> I have confirmed the behaviour by removing all config from the
> interface, stopping ntpd and then bringing up a v4 address (ifconfig
> em0 inet autoconf), starting ntpd and bringing up a v6 address
> (ifconfig em0 inet6 autoconf). ntpd never connects to the constraint
> servers, despite having a v6 address (and the constraint servers have
> AAAA records, obviously). Again, restarting ntpd when a v6 address is
> configured gets things going: constraint servers are reached just
> fine, and time is adjusted according to NTP.
>
> Paul 'WEiRD' de Weerd
I'll see if I can find the root cuase of this.
-Otto
