%general-entities; ]> $LastChangedBy$ $Date$ ntp The ntp package contains a client and server to keep the time synchronized between various computers over a network. This package is the official reference implementation of the NTP protocol. &lfs7a_checked; Package Information Download (HTTP): Download (FTP): Download MD5 sum: &ntp-md5sum; Download size: &ntp-size; Estimated disk space required: &ntp-buildsize; Estimated build time: &ntp-time; ntp Dependencies Required (runtime, for update-leap) and Optional , , , libedit, and libopts from AutoGen User Notes: There should be a dedicated user and group to take control of the ntpd daemon after it is started. Issue the following commands as the root user: groupadd -g 87 ntp && useradd -c "Network Time Protocol" -d /var/lib/ntp -u 87 \ -g ntp -s /bin/false ntp Install ntp by running the following commands: ./configure --prefix=/usr \ --bindir=/usr/sbin \ --sysconfdir=/etc \ --enable-linuxcaps \ --with-lineeditlibs=readline \ --docdir=/usr/share/doc/ntp-&ntp-version; && make To test the results, issue: make check. Now, as the root user: make install && install -v -o ntp -g ntp -d /var/lib/ntp --bindir=/usr/sbin: This parameter places the administrative programs in /usr/sbin. --enable-linuxcaps: ntpd is run as user ntp, so use Linux capabilities for non-root clock control. --with-lineeditlibs=readline: This switch enables Readline support for ntpdc and ntpq programs. If omitted, libedit will be used if installed, otherwise no readline capabilites will be compiled. /etc/ntp.conf /etc/ntp.conf The following configuration file first defines various ntp servers with open access from different continents. Second, it creates a drift file where ntpd stores the frequency offset and a pid file to store the ntpd process ID. Third, it defines the location for the leap-second definition file /etc/ntp.leapseconds, that the update-leap script checks and updates, when necessary. This script can be run as a cron job and the ntp developers recommend a frequency of about three weeks for the updates. Since the documentation included with the package is sparse, visit the ntp website at and for more information. cat > /etc/ntp.conf << "EOF" # Asia server 0.asia.pool.ntp.org # Australia server 0.oceania.pool.ntp.org # Europe server 0.europe.pool.ntp.org # North America server 0.north-america.pool.ntp.org # South America server 2.south-america.pool.ntp.org driftfile /var/lib/ntp/ntp.drift pidfile /var/run/ntpd.pid leapfile /etc/ntp.leapseconds EOF You may wish to add a Security session. For explanations, see . cat >> /etc/ntp.conf << "EOF" # Security session restrict default limited kod nomodify notrap nopeer noquery restrict -6 default limited kod nomodify notrap nopeer noquery restrict 127.0.0.1 restrict ::1 EOF There are two options. Option one is to run ntpd continuously and allow it to synchronize the time in a gradual manner. The other option is to run ntpd periodically (using cron) and update the time each time ntpd is scheduled. If you choose Option one, then install the /etc/rc.d/init.d/ntp init script ntpd.service unit included in the package. ntp ntpd.service make install-ntpd If you prefer to run ntpd periodically, add the following command to root's crontab: ntpd -q Execute the following command if you would like to set the hardware clock to the current system time at shutdown and reboot: ln -v -sf ../init.d/setclock /etc/rc.d/rc0.d/K46setclock && ln -v -sf ../init.d/setclock /etc/rc.d/rc6.d/K46setclock The other way around is already set up by LFS. Installed Programs Installed Libraries Installed Directories calc_tickadj, ntp-keygen, ntp-wait, ntpd, ntpdate, ntpdc, ntpq, ntptime, ntptrace, sntp, tickadj and update-leap None /usr/share/ntp, /usr/share/doc/ntp-4.2.8 and /var/lib/ntp Short Descriptions calc_tickadj calculates optimal value for tick given ntp drift file. calc_tickadj ntp-keygen generates cryptographic data files used by the NTPv4 authentication and identification schemes. ntp-keygen ntp-wait is useful at boot time, to delay the boot sequence until ntpd has set the time. ntp-wait ntpd is a ntp daemon that runs in the background and keeps the date and time synchronized based on response from configured ntp servers. It also functions as a ntp server. ntpd ntpdate is a client program that sets the date and time based on the response from an ntp server. This command is deprecated. ntpdate ntpdc is used to query the ntp daemon about its current state and to request changes in that state. ntpdc ntpq is a utility program used to monitor ntpd operations and determine performance. ntpq ntptime reads and displays time-related kernel variables. ntptime ntptrace traces a chain of ntp servers back to the primary source. ntptrace sntp is a Simple Network Time Protocol (SNTP) client. sntp tickadj reads, and optionally modifies, several timekeeping-related variables in older kernels that do not have support for precision timekeeping. tickadj update-leap is a script to verify and, if necessary, update the leap-second definition file. update-leap