Provided by: htpdate_1.1.3-1_i386 bug

NAME

       htpdate - Time synchronization (daemon)

SYNOPSIS

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

DESCRIPTION

       The  HTTP  Time Protocol (HTP) is used to synchronize a computer's time
       with web servers as reference time source. Htp  will  synchronize  your
       computer's  time to Greenwich Mean Time (GMT) via HTTP headers from web
       servers.  The htpdate package includes a  program  for  retrieving  the
       date and time from remote machines via a network. Htpdate works through
       proxy servers. Accuracy of htpdate will be usually within  0.5  seconds
       (better with multiple servers). If this is not good enough for you, try
       the ntpd package.

OPTIONS

       -0     HTTP/1.0 request (default is HTTP/1.1).

       -4     Force IPv4 name resolution only. Default  behaviour  is  to  try
              IPv6 first and fall back to IPv4.

       -6     Force IPv6 name resolution only.

       -a     Adjust time smoothly (default in daemon mode).

       -b     Burst  mode  uses  multiple polls for each web server to enhance
              accuracy.

       -d     Turn debug on. Shows the "raw" timestamp, round trip time,  time
              delta  and  and basic statistics of web server responses. Useful
              to determining the quality of a  specific  web  server  as  time
              source.

       -h     Show help.

       -i     Set the pid file (default /var/run/htpdate.pid).

       -l     Use   syslog  for  output  (levels  LOG_WARNING  and  LOG_INFO).
              Convenient if you use htpdate from cron.

       -m -M  These options specify the minimum (-m) and maximum (-M)  polling
              intervals  for  HTP  requests,  in seconds. The default range is
              between 30 minutes and 32 hours. Htpdate calculates the  optimal
              polling  frequency  between  minimum  and  maximum  values. Only
              applicable when running in daemon mode.

       -p     Precision (in milliseconds) specifies the operating accuracy  of
              htpdate. Internally htpdate uses a different algorithm to detect
              a time offset, when precision is specified. Precision  only  has
              effect in daemon mode. Use with causion.

       -q     Query  web  server  and  display  time,  but  do not change time
              (default in interactive mode).

       -s     Set time immediate. In daemon mode -s  only  applies  the  first
              poll.

       -t     Turn off sanity time check. By default a time offset larger than
              a year, compared to current localtime, is rejected. With -t set,
              any time stamp will be accepted.

       -u     Set the user and group that the server normally runs at (default
              is root).

       -x     Let htpdate compensate for the systematisch clock drift.

       -D     Run as daemon (requires root privileges).

       -P     Proxy server hostname or ip-address.

       host   Web  server  hostname  or  ip-address.  Upto  16  hosts  may  be
              specified,  but  in  general 3 to 5 hosts should be enough for a
              redundant and accurate setup.

       port   Portnumber (default 80 and 8080 for proxy server)

EXAMPLES

       Request time from web server (don't update local clock):
              htpdate -q www.linux.org www.freebsd.org

       Verbose output (don't update local clock):
              htpdate -d -q www.linux.org www.freebsd.org

       Adjust time smoothly and log output to syslog (eg. cron):
              htpdate -a -l www.linux.org www.freebsd.org

       HTTP/1.0 request in IPv6 literal format (RFC 2732):
              htpdate -0 [2001:DB8:1af6::123]:80

       Run htpdate as daemon:
              htpdate -D www.linux.org www.freebsd.org

       Daemon mode for the security minded:
              htpdate -D -u nobody:nogroup www.linux.org www.freebsd.org

AUTHOR

       Eddy Vervest <eddy@vervest.org>, http://www.vervest.org/htp

SEE ALSO

       rdate, timed, ntpd, adjtimex, ntp_adjtime,
       HTP implementation by Roy Keene (http://www.rkeene.org/oss/htp/)