[time-nuts] Re: NIST NTP servers way off for anyone else?

[Avamander]

> The hardware are done by the network PHY and need 1588 support in the
driver, which is not common.

PTP HW timestamping is thankfully a bit more common than NTP one. From
which you can deduce that it's unlikely you'll get HW timestamping in NTP
context.

However, new Chrony has support for encapsulating NTP in PTP to utilize the
HW timestamping support for PTP. Thought I'd mention.

On Wed, Dec 15, 2021 at 4:03 AM Trent Piepho <tpiepho at gmail.com> wrote:

> On Tue, Dec 14, 2021 at 2:21 PM Hal Murray <halmurray at sonic.net> wrote:
> >
> > > I've seen cards (ethtool) that support several time options - what
> are  they
> > > and how do I use them?
> >
> > I'm not sure which options you are referring to.
>
> Probably the flags from ethtool -T output:
>
> Time stamping parameters for eth0:
> Capabilities:
>     hardware-transmit     (SOF_TIMESTAMPING_TX_HARDWARE)
>     software-transmit     (SOF_TIMESTAMPING_TX_SOFTWARE)
>     hardware-receive      (SOF_TIMESTAMPING_RX_HARDWARE)
>     software-receive      (SOF_TIMESTAMPING_RX_SOFTWARE)
>     software-system-clock (SOF_TIMESTAMPING_SOFTWARE)
>     hardware-raw-clock    (SOF_TIMESTAMPING_RAW_HARDWARE)
>
> The software ones are normally alway present and are what you describe
> with the kernel's timestamping.  The hardware are done by the network
> PHY and need 1588 support in the driver, which is not common.  I don't
> think any of the RPis support it.
>
> >
> > You can't have boxes on the internet update packets if you are
> interested in
> > security.
>
> That seems too restrictive.  Consider that TLS doesn't include the
> TCP/IP header, which can be modified by IP fragmentation, and that is
> still considered secure.
>
> I think one could design a protocol such that each appended timestamp
> is signed, and included a digest of all timestamps before it, so that
> while one does not trust every timestamp in the chain, it can be
> trusted that each timestamp was generated by entity that said it
> generated it and that any timestamps generated by a trusted entity
> were not later modified by a untrusted one.
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