[ntp:questions] Making a clock tell the wrong time?

Mike K Smith mks-usenet at dsl.pipex.com
Mon Mar 9 17:04:01 UTC 2009


Hi,

For testing purposes I want to configure an NTP server to run with a
small but known offset. I would like to test at the following offset
values 25, 90, 180, 350 and 2500ms.

I tried the naive approach first - I synced a Linux PC to a stratum 1
server and once it was stable I reconfigured NTP to run the local
clock at stratum 0 with a fudge line to set the time1 parameter to
90ms.

The server showed a 90ms offset after the first poll of the local
clock, but within a few poll cycles it had discarded the offset.

If instead of the local clock I can arrange a serial feed and apply an
offset to that via time1, will it have the desired effect, i.e.
keeping the PC clock synced via the serial, but applying the offset to
the time it provides via NTP?

Is there another quick simple way of providing a one-off offset to the
local clock and then allowing it to free-run?




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