From owner-freebsd-security@freebsd.org Sat Apr 30 13:55:06 2016 Return-Path: Delivered-To: freebsd-security@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7A5A2B1FD4C for ; Sat, 30 Apr 2016 13:55:06 +0000 (UTC) (envelope-from news@mips.inka.de) Received: from mail.inka.de (quechua.inka.de [IPv6:2a04:c9c7:0:1073:217:a4ff:fe3b:e77c]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 45BB21F7B for ; Sat, 30 Apr 2016 13:55:06 +0000 (UTC) (envelope-from news@mips.inka.de) Received: from mips.inka.de (news@[127.0.0.1]) by mail.inka.de with uucp (rmailwrap 0.5) id 1awVMO-00037n-Ro; Sat, 30 Apr 2016 15:55:04 +0200 Received: from lorvorc.mips.inka.de (localhost [127.0.0.1]) by lorvorc.mips.inka.de (8.15.2/8.15.2) with ESMTP id u3UDqLc2074281 for ; Sat, 30 Apr 2016 15:52:21 +0200 (CEST) (envelope-from news@lorvorc.mips.inka.de) Received: (from news@localhost) by lorvorc.mips.inka.de (8.15.2/8.15.2/Submit) id u3UDqLTd074280 for freebsd-security@freebsd.org; Sat, 30 Apr 2016 15:52:21 +0200 (CEST) (envelope-from news) To: freebsd-security@freebsd.org From: Christian Weisgerber Newsgroups: list.freebsd.security Subject: Re: FreeBSD Security Advisory FreeBSD-SA-16:16.ntp Date: Sat, 30 Apr 2016 13:52:21 +0000 (UTC) Message-ID: References: <20160429082953.DB31D1769@freefall.freebsd.org> <9e6342a420259fec7bd21d6222cc6e05@zahemszky.hu> <1461929003.67736.2.camel@yandex.com> <201604300015.u3U0FB3k058050@lorvorc.mips.inka.de> User-Agent: slrn/1.0.2 (FreeBSD) X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 30 Apr 2016 13:55:06 -0000 On 2016-04-29, Roger Marquis wrote: >> While I cannot speak for anyone other than myself, the two simply aren't >> equivalent. As a conscious design choice, OpenNTPD trades off accuracy >> for code simplicity. > > IIRC openntpd is accurate down to ~100ms. I have no idea where you get that absurd number from. OpenNTPD is accurate at least down to 1 ms. I don't have better time sources. $ ntpctl -sa 1/1 peers valid, clock synced, stratum 2 peer wt tl st next poll offset delay jitter 2001:6f8:124a::8 ntp * 1 10 1 250s 1506s -0.193ms 0.493ms 0.067ms -- Christian "naddy" Weisgerber naddy@mips.inka.de