NAME

       rdate — set the system's date from a remote host

SYNOPSIS

       rdate [-46acnpsuv] [-o port] host

DESCRIPTION

       rdate displays and sets the local date and time from the host name or address given as the argument.  The
       time  source may be an RFC 868 TCP protocol server, which is usually implemented as a built-in service of
       inetd(8), or an RFC 2030 protocol SNTP/NTP server.  By default, rdate uses the RFC 868 TCP protocol.

       The options are as follows:

       -4      Forces rdate to use IPv4 addresses only.

       -6      Forces rdate to use IPv6 addresses only.

       -a      Use the adjtime(2) call to gradually skew the local time to the  remote  time  rather  than  just
               hopping.

       -c      Correct   leap   seconds.   Sometimes  required  when  synchronizing  to  an  NTP  server.   When
               synchronizing using the RFC 868 protocol, use this option only if the server does  not  correctly
               account  for  leap  seconds.  You can determine if you need this parameter if you sync against an
               NTP server (with this parameter) or (recommended) check with a local radio  controlled  watch  or
               phone service.

       -n      Use SNTP (RFC 2030) instead of the RFC 868 time protocol.

       -o port
               Use port port instead of port 37.

       -p      Do not set, just print the remote time.

       -s      Do not print the time.

       -u      Use UDP instead of TCP as transport.

       -v      Verbose output.  Always show the adjustment.

FILES

       /var/log/wtmp  record of date resets and time changes

EXAMPLES

       To     get     the     legal     time     in    Germany,    set    the    /etc/localtime    symlink    to
       /usr/share/zoneinfo/right/Europe/Berlin and issue the following command:

             # rdate -ncv ptbtime1.ptb.de

       The command of course assumes you have a working internet connection and DNS set up  to  connect  to  the
       server at Physikalisch-Technische Bundesanstalt in Braunschweig, Germany.

       To  gradually  adjust  time  once  an hour after the first "step" adjustment, put the following line into
       root's crontab:

             58  *  *  *  *  rdate -ncav ptbtime1.ptb.de | logger -t NTP

       To to set the time through an ssh tunnel, use something like so:

             ssh -f -L 10037:time.example.com:37 tyr.example.com sleep 10
             rdate -a -o 10037 locahost

SEE ALSO

       date(1), adjtime(2), inetd(8), ntpd(8), timed(8)

AUTHORS

       This manual page was written by Christos Zoulas. It was changed by
       Anibal Monsalve Salazar for the Debian Project.

Debian                                            May 31, 2007                                          RDATE(8)