[ntp:questions] Problem syncing NTP behind NAT

Dave Hart hart at ntp.org
Fri Apr 6 03:27:41 UTC 2012

On Fri, Apr 6, 2012 at 02:38, Ken Link <klink at numberzero.org> wrote:
> Now I stop NTP on machine A and start NTP on machine B. The client
> request goes out the NAT, and I see the request coming into the
> external server with tcpdump. But, NTP on the external server doesn't
> respond. In fact, the debug from NTP doesn't even have a "receive"
> line for the request.

That's the key point.  I don't know how you can expect ntpd to respond
to a packet it doesn't receive.  There is some difference, probably to
be seen in comparing the tcpdump output, to explain why the request
never makes it to ntpd.

Good luck,
Dave Hart

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