Hello, Antonio,

thanks for your informative answer! I hope you take no offense at my mistrust,
but I rather be careful.

To tie up the loose ends first:

* I mixed up ntpq and ntpdc, sorry! (Either of which could be used for ntp
verification purposes.)

* jquery is a well-known Javascript framework with a good reputation, used by
many web sites out there. A production server's version will sacrifice
readability for shorter size - this is completely normal.

* _Signed_  Java programs can do pretty much anything an installed application
can do. One explicitly extends trust to the applet signer, invites him in to
control one's computer. If one doesn't do that, the applet doesn't run.

The approach Antonio describes can work.

However, there are some reliability issues.

A while ago, I installed ntpd on a Windows PC, to some location not easily
guessable, under a privileged user's account different from the unprivileged one
I normally use, and I'm not sure that installation is in any user's PATH. Such
an installation would be difficult to verify with the "run ntpd" approach.

Even worse: The ntpd program may run smoothly and keep the computer's time
precisely, yet, that ntpd may be configured in such a way that it reacts only to
packets that answer queries it itself has sent. Such an installation would be
difficult to verify with any approach short of reading logs.

These are extreme cases. The approach described can verify ntpd installation in
the many more common cases.

It still does not suite my personal taste. Call it "German Angst". But I do not
like the idea to allow some whatever from a web site out of the depths of the
internet to execute arbitrary programs on my computer.


Here are two more ideas I want to throw into the air. Both do without execution
privileges for arbitrary programs on my PC. If anybody likes any of these ideas,
catch them and run with them.

First idea: If I thought that the output of ntpq is too cryptic, I would
consider to grab the sources of that program and add something like

ntpq -c healthcheck

This should give a cooked nice output comprehensible by an average user.

Then I'd try to see whether this contribution gets accepted into the official
ntp distribution.


Secondly, there is ntpd and there are a host of other time keeping solutions out
there. One might want to universally verify any of these by the outcome: How
precise is my computer's clock?

It would be useful, and is quite possible, to implement a simple ntp client with
Javascript, based on web sockets. That client would be part of a web page that
gets served by some web server machine, a machine which also runs an ntp server.
On browsing to that web page, the user would get immediate (or almost immediate)
feed back: "Your PC's clock is slow by 4 minutes 21 seconds." Or something of
that sort. It would also be possible to use HTTP instead of NTP, for much
increased probability that this works through intervening firewalls, paid for
with a decrease in precision.

Best regards all around,

Andreas

_______________________________________________
pool mailing list
[email protected]
http://lists.ntp.org/listinfo/pool

Reply via email to