Re: [Ntp] Symmetric mode

[Miroslav Lichvar <[e-mail]>]

On Tue, Sep 20, 2022 at 09:41:38AM -0400, Danny Mayer wrote:
> On 9/19/22 5:01 AM, Miroslav Lichvar wrote:
> > It's not very useful. I think the most interesting thing about it is
> > that sources using the symmetric mode are marked differently in tools
> > like ntpq, so it's more obvious to the admin that synchronization can
> > work in both directions.
> It's extremely useful, particularly when you end up in orphan mode or just
> need to make sure that all systems in the local network are synchronized.

You said that before. If there is doubt, you need to provide some
evidence. This is not a debate on TV where repeating something over in
an authoritative voice would change someone's mind.

You claim that something exists, that there is something special about
symmetric mode with respect to orphan mode or source selection in
general. That's easy for you to prove that. You just need to point to
an exact location in the source code or RFC and we can easily confirm
if that is true.

I claim that there is no such thing, that there is no difference
between selection of sources using the client/server mode and
symmetric mode. It's much more difficult for me to prove that
something doesn't exist. I can point to the source code where I'd
expect it to be, like this location in the clock_select() function

https://fossies.org/linux/misc/ntp-4.2.8p15.tar.gz/ntp-4.2.8p15/ntpd/ntp_proto.c#l_3531

where I don't see anything checking the mode (MODE_SERVER vs
MODE_ACTIVE/MODE_PASSIVE), but that doesn't mean this distinction
couldn't be hidden somewhere else.

It's up to you to prove that it exists.

-- 
Miroslav Lichvar