From owner-freebsd-hackers@freebsd.org Tue Oct 9 05:29:47 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0C4D310BFED7 for ; Tue, 9 Oct 2018 05:29:47 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from vtr.rulingia.com (vtr.rulingia.com [IPv6:2001:19f0:5801:ebe:5400:1ff:fe53:30fd]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "vtr.rulingia.com", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 500F775FFB for ; Tue, 9 Oct 2018 05:29:45 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from server.rulingia.com (ppp59-167-167-3.static.internode.on.net [59.167.167.3]) by vtr.rulingia.com (8.15.2/8.15.2) with ESMTPS id w995TYef043687 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 9 Oct 2018 16:29:40 +1100 (AEDT) (envelope-from peter@rulingia.com) X-Bogosity: Ham, spamicity=0.000000 Received: from server.rulingia.com (localhost.rulingia.com [127.0.0.1]) by server.rulingia.com (8.15.2/8.15.2) with ESMTPS id w995TO0K021070 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 9 Oct 2018 16:29:25 +1100 (AEDT) (envelope-from peter@server.rulingia.com) Received: (from peter@localhost) by server.rulingia.com (8.15.2/8.15.2/Submit) id w995TO9Q021069; Tue, 9 Oct 2018 16:29:24 +1100 (AEDT) (envelope-from peter) Date: Tue, 9 Oct 2018 16:29:24 +1100 From: Peter Jeremy To: Wojciech Puchar Cc: freebsd-hackers@freebsd.org Subject: Re: ntpd strange problem Message-ID: <20181009052924.GJ21091@server.rulingia.com> References: <20181005061829.GG21091@server.rulingia.com> <1538855151.14264.54.camel@freebsd.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="K/NRh952CO+2tg14" Content-Disposition: inline In-Reply-To: X-PGP-Key: http://www.rulingia.com/keys/peter.pgp User-Agent: Mutt/1.10.0 (2018-05-17) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Oct 2018 05:29:47 -0000 --K/NRh952CO+2tg14 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2018-Oct-08 13:19:18 +0200, Wojciech Puchar wrote: >After week or so it got out of sync in spite of ntpd still running. > >Strange but today (4 days after i restarted ntpd) it seems to be in sync A couple of suggestions: * (especially if you have an ADSL link): The NTP protocol assumes that the path between the client and server are have symmetric timing. In my experience, bulk uploads or downloads can cause significant path delay asymmetries, which can confuse ntpd. * You only have a single server and are therefore dependent on the trustworthiness of that server. A few more servers could be useful. You could try adding enabling some monitoring (eg loopstats and peerstats) and see what is happening leading up to ntpd losing sync. --=20 Peter Jeremy --K/NRh952CO+2tg14 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE7rKYbDBnHnTmXCJ+FqWXoOSiCzQFAlu8PLRfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEVF QjI5ODZDMzA2NzFFNzRFNjVDMjI3RTE2QTU5N0EwRTRBMjBCMzQACgkQFqWXoOSi CzSkog/+I7lIuVmwdIJWV1T78GObZnJwK/H3XRW6wFSXGnmkM0z5Psxrn+ezakWw 6SdQZYvr092QyO3HsYXacOaKFWR+EzObWZp99U8hlFq+RWig1if8WxpgzCakHPxb TLRBRbPBwu0UTz5zzbMr0hkmAs1dA7P04Qu3OnivRq6QN658ozw4x3iur4dpCqlM 6ynyNEql+I0tjfLEa2VFLa6q90lHQE380JpZinr9w7C3QnFolmA5CNQMSxp/Gl9v TysqdaJR6fvfSOqbt2W6wtTOqdcn9oH3JHD3vVrXcBcXMDO0zojkd0jha56sTHyy PWqLB4XhNQ/R88w0U5jdRR4WAkdgbYPcTCFhWvTTK5pp6SIEg9kZhaq8cQgEG9Em ygwMALWnt2g4fPacLhcx9Ybs0MTYzK/q2+aIzITJQACCo81T0dG2b7JySJihih8a if/dR+7HSWwDwlu3amt9xdml8UhCLyAa5EYb3rMYeO4v7bItI7V+xYTyn2lsL0Ol ilaPio92N3wcVYN5BDVxzjK+1gTckIcdnNMSroizJmWT1OlvmCwF9MW5CpbgifGH Se3QRTj4yN1NgWENjoe6aqffkaU/rYh0s+kRz2lV52oc38WkTwRNRvDH7ik+Hr9k +VefnPXCyJhXzG+6UfFvYONoO2Ah4NfkzQZ7KI0VtrT//qqVQBY= =K3YB -----END PGP SIGNATURE----- --K/NRh952CO+2tg14--