From owner-freebsd-questions@FreeBSD.ORG Tue Apr 21 18:29:22 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0235C106564A for ; Tue, 21 Apr 2009 18:29:22 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout014.mac.com (asmtpout014.mac.com [17.148.16.89]) by mx1.freebsd.org (Postfix) with ESMTP id DE5208FC1F for ; Tue, 21 Apr 2009 18:29:21 +0000 (UTC) (envelope-from cswiger@mac.com) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Received: from cswiger1.apple.com ([17.227.140.124]) by asmtp014.mac.com (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTPSA id <0KIG002IPRCUKH80@asmtp014.mac.com> for freebsd-questions@freebsd.org; Tue, 21 Apr 2009 11:29:20 -0700 (PDT) Message-id: <344D9702-C894-4E54-B256-43FAB17903F1@mac.com> From: Chuck Swiger To: Mel Flynn In-reply-to: <200904212023.14365.mel.flynn+fbsd.questions@mailing.thruhere.net> Date: Tue, 21 Apr 2009 11:29:18 -0700 References: <200904211106.01965.mel.flynn+fbsd.questions@mailing.thruhere.net> <200904211643.32448.mel.flynn+fbsd.questions@mailing.thruhere.net> <20090421183133.4e0c414f@gumby.homeunix.com> <200904212023.14365.mel.flynn+fbsd.questions@mailing.thruhere.net> X-Mailer: Apple Mail (2.930.3) Cc: "freebsd-questions@freebsd.org Questions -" Subject: Re: Preventing ntpd from adjusting time (backwards) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Apr 2009 18:29:22 -0000 On Apr 21, 2009, at 11:23 AM, Mel Flynn wrote: > Now I'm also wondering how ntpd handles securelevel 2. "man init" suggests that stepping the clock by more than a second is disallowed: 2 Highly secure mode - same as secure mode, plus disks may not be opened for writing (except by mount(2)) whether mounted or not. This level precludes tampering with file systems by unmounting them, but also inhibits running newfs(8) while the system is multi- user. In addition, kernel time changes are restricted to less than or equal to one second. Attempts to change the time by more than this will log the message ``Time adjustment clamped to +1 second''. Regards, -- -Chuck