Htpdate

The HTTP Time Protocol (HTP) is used to synchronize a computer's time with web servers as reference time source. Htpdate will synchronize your computer's time by extracting timestamps from HTTP headers found in web server responses. Htpdate can be used as a daemon, to keep your computer synchronized. The accuracy of htpdate is at least -+0.5 seconds (better with multiple servers). If this is not good enough for you, try the ntpd package.

Install the htpdate package if you need tools for keeping your system's time synchronized via the HTP protocol. Htpdate works also through proxy servers.

Installation from source

Tested on Linux and FreeBSD only, but should work for most Unix flavors.

$ tar zxvf htpdate-x.y.z.tar.gz
    or
$ tar jxvf htpdate-x.y.z.tar.bz2
$ cd htpdate-X.Y.Z
$ make
$ make install

An example init script (scripts/htpdate.init) for use in /etc/init.d/ is included, but not installed automatically. This scripts with run htpdate as a daemon.

Another option is to use htpdate in a cronjob and start it periodically from cron. For a daily time sync it would look something like this: 5 3 * /usr/bin/htpdate -s www.linux.org www.freebsd.org

Installation from RPM

The easiest way to install (Redhat, SuSE, Mandriva etc..)

$ rpm -Uvh htpdate-x.y.z.i386.rpm

By default the htpdate daemon is activated (with chkconfig). If you only want to run htpdate from cron, disable the htpdate service with 'chkconfig --del htpdate'.

Usage

Usage: htpdate [-046abdhlqstxD] [-i pid file] [-m minpoll] [-M maxpoll] [-p precision] [-P [:port]] [-u user[:group]] <host[:port]> ...

E.g. htpdate -q www.linux.org www.freebsd.org

In general, if more web servers are specified, the accuracy will increase.

See manpage for more details.

To do

• I'm open for suggestions :)