From owner-svn-doc-head@FreeBSD.ORG Fri Jan 31 21:54:18 2014 Return-Path: Delivered-To: svn-doc-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E63FFCD3; Fri, 31 Jan 2014 21:54:18 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id B83CB1DAF; Fri, 31 Jan 2014 21:54:18 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.7/8.14.7) with ESMTP id s0VLsIWV021561; Fri, 31 Jan 2014 21:54:18 GMT (envelope-from dru@svn.freebsd.org) Received: (from dru@localhost) by svn.freebsd.org (8.14.7/8.14.7/Submit) id s0VLsI7D021560; Fri, 31 Jan 2014 21:54:18 GMT (envelope-from dru@svn.freebsd.org) Message-Id: <201401312154.s0VLsI7D021560@svn.freebsd.org> From: Dru Lavigne Date: Fri, 31 Jan 2014 21:54:18 +0000 (UTC) To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r43711 - head/en_US.ISO8859-1/books/handbook/network-servers X-SVN-Group: doc-head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-doc-head@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: SVN commit messages for the doc tree for head List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 31 Jan 2014 21:54:19 -0000 Author: dru Date: Fri Jan 31 21:54:18 2014 New Revision: 43711 URL: http://svnweb.freebsd.org/changeset/doc/43711 Log: White space fix only. Translators can ignore. Sponsored by: iXsystems Modified: head/en_US.ISO8859-1/books/handbook/network-servers/chapter.xml Modified: head/en_US.ISO8859-1/books/handbook/network-servers/chapter.xml ============================================================================== --- head/en_US.ISO8859-1/books/handbook/network-servers/chapter.xml Fri Jan 31 21:35:11 2014 (r43710) +++ head/en_US.ISO8859-1/books/handbook/network-servers/chapter.xml Fri Jan 31 21:54:18 2014 (r43711) @@ -5228,39 +5228,38 @@ Starting smbd. Clock Synchronization with NTP NTP - ntpd + ntpd - Over time, a computer's clock is prone to drift. This is - problematic as many network services require the computers on a network - to share the same accurate time. Accurate time is also needed to ensure - that file timestamps stay - consistent. The - Network Time Protocol (NTP) is one way to provide clock - accuracy in a network. - - &os; includes &man.ntpd.8; - which can be configured to query other - NTP servers in order to - synchronize the clock on that machine or to provide time services to - other computers in the network. The servers which are queried - can be local to the network or provided by an ISP. - In addition, an online - list of publicly accessible NTP servers - is available. When choosing a public NTP server, select - one that is geographically close and - review its usage policy. - - Choosing several NTP servers is recommended in - case one of the servers becomes unreachable or - its clock proves unreliable. As ntpd receives responses, - it favors - reliable servers over the less reliable ones. - - This section describes how to configure ntpd on &os;. Further documentation can be found in - /usr/share/doc/ntp/ in HTML - format. + Over time, a computer's clock is prone to drift. This is + problematic as many network services require the computers on a + network to share the same accurate time. Accurate time is also + needed to ensure that file timestamps stay consistent. The + Network Time Protocol (NTP) is one way to + provide clock accuracy in a network. + + &os; includes &man.ntpd.8; which can be configured to query + other NTP servers in order to synchronize the + clock on that machine or to provide time services to other + computers in the network. The servers which are queried can be + local to the network or provided by an ISP. + In addition, an online + list of publicly accessible NTP + servers is available. When choosing a public + NTP server, select one that is geographically + close and review its usage policy. + + Choosing several NTP servers is + recommended in case one of the servers becomes unreachable or + its clock proves unreliable. As ntpd + receives responses, it favors reliable servers over the less + reliable ones. + + This section describes how to configure + ntpd on &os;. Further documentation + can be found in /usr/share/doc/ntp/ in HTML + format. <acronym>NTP</acronym> Configuration @@ -5270,115 +5269,117 @@ Starting smbd. ntpdate - To only synchronize the clock when a system boots, - use &man.ntpdate.8;. This alone can be appropriate for - desktops which are frequently rebooted. However, - most systems should - run ntpdate at boot time as well as configure ntpd. - This is because ntpd - changes the clock gradually, whereas ntpdate - sets the clock, no matter how great the difference between a - machine's current clock setting and the correct time. - - To enable ntpdate at boot time, add - ntpdate_enable="YES" to - /etc/rc.conf. To also enable - ntpd, add the ntpd_enable="YES" - entry to /etc/rc.conf. Additional variables can be specified - in /etc/rc.conf. Refer to &man.rc.conf.5;, - &man.ntpdate.8;, and &man.ntpd.8; for details. - - Both applications - read /etc/ntp.conf to determine - which servers to query. Here is a simple example of an - /etc/ntp.conf: + To only synchronize the clock when a system boots, use + &man.ntpdate.8;. This alone can be appropriate for desktops + which are frequently rebooted. However, most systems should + run ntpdate at boot time as well as + configure ntpd. This is because + ntpd changes the clock gradually, + whereas ntpdate sets the clock, no + matter how great the difference between a machine's current + clock setting and the correct time. + + To enable ntpdate at boot time, + add ntpdate_enable="YES" to + /etc/rc.conf. To also enable + ntpd, add the + ntpd_enable="YES" entry to + /etc/rc.conf. Additional variables can + be specified in /etc/rc.conf. Refer to + &man.rc.conf.5;, &man.ntpdate.8;, and &man.ntpd.8; for + details. + + Both applications read /etc/ntp.conf + to determine which servers to query. Here is a simple example + of an /etc/ntp.conf: - - Sample <filename>/etc/ntp.conf</filename> + + Sample <filename>/etc/ntp.conf</filename> server ntplocal.example.com prefer server timeserver.example.org server ntp2a.example.net driftfile /var/db/ntp.drift - + - The format of this file is - described in &man.ntp.conf.5;. The server option specifies which - servers to query, with one server listed on each line. - If a server entry includes prefer, - that server is preferred over other servers. A response - from a preferred server will be discarded if it differs - significantly from responses; otherwise it - will be used. - The prefer argument should only be used for - NTP servers that are known to be highly accurate, such as - those with special time monitoring hardware. - - The driftfile entry specifies which - file is used to store the system clock's frequency offset. - ntpd uses this to automatically - compensate for the clock's natural drift, allowing it to - maintain a reasonably correct setting even if it is cut off - from all external time sources for a period of time. This - file also stores information about previous responses - from NTP servers. Since this file contains - internal information for NTP, it should not be modified. - - By default, an NTP server is accessible to any - network host. The restrict - option in /etc/ntp.conf can be used to - control which systems can access the server. For example, - to deny all machines from accessing the NTP - server, add the following line to - /etc/ntp.conf: + The format of this file is described in &man.ntp.conf.5;. + The server option specifies which servers + to query, with one server listed on each line. If a server + entry includes prefer, that server is + preferred over other servers. A response from a preferred + server will be discarded if it differs significantly from + responses; otherwise it will be used. The + prefer argument should only be used for + NTP servers that are known to be highly + accurate, such as those with special time monitoring + hardware. + + The driftfile entry specifies which + file is used to store the system clock's frequency offset. + ntpd uses this to automatically + compensate for the clock's natural drift, allowing it to + maintain a reasonably correct setting even if it is cut off + from all external time sources for a period of time. This + file also stores information about previous responses + from NTP servers. Since this file contains + internal information for NTP, it should not + be modified. + + By default, an NTP server is accessible + to any network host. The restrict option + in /etc/ntp.conf can be used to control + which systems can access the server. For example, to deny all + machines from accessing the NTP server, add + the following line to + /etc/ntp.conf: - restrict default ignore + restrict default ignore - This will also prevent access from other NTP servers. - If there is a - need to synchronize with an external NTP + This will also prevent access from other + NTP servers. If there is a need to + synchronize with an external NTP server, allow only that specific server. Refer to &man.ntp.conf.5; for more information. - To allow machines within the network to synchronize - their clocks with the server, but ensure they are not - allowed to configure the server or be used as peers to - synchronize against, instead use: - - restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap - - where - 192.168.1.0 is the - local network address and - 255.255.255.0 is - the network's subnet mask. - - Multiple restrict entries are supported. - For more - details, refer to the Access Control Support - subsection of &man.ntp.conf.5;. - - Once - ntpd_enable="YES" has been added to - /etc/rc.conf, ntpd - can be started now without rebooting the system by typing: + To allow machines within the network to synchronize their + clocks with the server, but ensure they are not allowed to + configure the server or be used as peers to synchronize + against, instead use: + + restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap + + where 192.168.1.0 is the local + network address and 255.255.255.0 is the network's + subnet mask. + + Multiple restrict entries are + supported. For more details, refer to the Access + Control Support subsection of + &man.ntp.conf.5;. + + Once ntpd_enable="YES" has been added + to /etc/rc.conf, + ntpd can be started now without + rebooting the system by typing: &prompt.root; service ntpd start - Using <acronym>NTP</acronym> with a <acronym>PPP</acronym> - Connection + Using <acronym>NTP</acronym> with a + <acronym>PPP</acronym> Connection ntpd does not need a permanent connection to the Internet to function properly. However, if a PPP connection is configured to dial out - on demand, NTP traffic should be prevented from - triggering a dial out or keeping the connection alive. This can be configured - with filter + on demand, NTP traffic should be prevented + from triggering a dial out or keeping the connection alive. + This can be configured with filter directives in /etc/ppp/ppp.conf. For example: @@ -5398,8 +5399,8 @@ driftfile /var/db/ntp.drift Some Internet access providers block low-numbered ports, - preventing NTP from functioning since replies never - reach the machine. + preventing NTP from functioning since replies never reach + the machine.