Standard Simple Network Time Protocol client program


sntp  [-flags]  [-flag [value]] [--option-name[[=| ]value]] [ hostname-or-IP ...]

Runs on:

QNX Neutrino

       sntp can be used as an SNTP client to query a NTP or  SNTP  server  and
       either  display the time or set the local system's time (given suitable
       privilege).  It can be run as an interactive command  or  from  a  cron
       job.  NTP (the Network Time Protocol) and SNTP (the Simple Network Time
       Protocol) are defined and described by RFC 5905.

       The default is to write the estimated correct local date and time (i.e.
       not  UTC)  to  the  standard  output  in  a  format  like:  '1996-10-15
       20:17:25.123 (+0800) +4.567 +/- 0.089 [host] IP sN' where the '(+0800)'
       means  that  to  get to UTC from the reported local time one must add 8
       hours and 0 minutes, the '+4.567' indicates the local  clock  is  4.567
       seconds  behind the correct time (so 4.567 seconds must be added to the
       local clock to get it to be correct).  Note that the number of decimals
       printed  for  this value will change based on the reported precision of
       the server.  '+/- 0.089' is the reported synchronization  distance  (in
       seconds), which represents the maximum error due to all causes.  If the
       server does not report valid data needed to calculate the  synchroniza-
       tion  distance,  this will be reported as '+/- ?'.  If the host is dif-
       ferent from the IP, both will be displayed.  Otherwise, only the IP  is
       displayed.   Finally,  the stratum of the host is reported and the leap
       indicator is decoded and displayed.

       -4, --ipv4
              Force IPv4 DNS name resolution.  This option must not appear  in
              combination with any of the following options: ipv6.

              Force  DNS resolution of the following host names on the command
              line to the IPv4 namespace.

       -6, --ipv6
              Force IPv6 DNS name resolution.  This option must not appear  in
              combination with any of the following options: ipv4.

              Force  DNS resolution of the following host names on the command
              line to the IPv6 namespace.

       -a auth-keynumber, --authentication=auth-keynumber
              Enable authentication with the key auth-keynumber.  This  option
              takes an integer number as its argument.

              Enable  authentication  using the key specified in this option's
              argument.  The argument of this option is the  keyid,  a  number
              specified in the keyfile as this key's identifier.  See the key-
              file option (-k) for more details.

       -b broadcast-address, --broadcast=broadcast-address
              Listen to the address specified for broadcast time  sync.   This
              option may appear an unlimited number of times.

              If  specified  sntp will listen to the specified address for NTP
              broadcasts.  The default maximum wait  time  can  (and  probably
              should) be modified with -t.

       -c host-name, --concurrent=host-name
              Concurrently  query all IPs returned for host-name.  This option
              may appear an unlimited number of times.

              Requests from an NTP "client" to a "server" should never be sent
              more  rapidly  than  one  every  2 seconds.  By default, any IPs
              returned as part of a DNS lookup are assumed to be for a  single
              instance  of ntpd, and therefore sntp will send queries to these
              IPs one after another, with  a  2-second  gap  in  between  each

              The  -c  or --concurrent flag says that any IPs returned for the
              DNS lookup of the supplied host-name are on different  machines,
              so we can send concurrent queries.

       -d, --debug-level
              Increase  debug  verbosity  level.   This  option  may appear an
              unlimited number of times.

       -D number, --set-debug-level=number
              Set the debug verbosity level.  This option may appear an unlim-
              ited  number  of  times.  This option takes an integer number as
              its argument.

       -g milliseconds, --gap=milliseconds
              The gap (in milliseconds) between time  requests.   This  option
              takes  an integer number as its argument.  The default millisec-
              onds for this option is:

              Since we're only going to use the first valid  response  we  get
              and  there  is benefit to specifying a good number of servers to
              query, separate the queries we send out by the specified  number
              of milliseconds.

       -K file-name, --kod=file-name
              KoD history filename.  The default file-name for this option is:

              Specifies  the filename to be used for the persistent history of
              KoD responses received from  servers.   If  the  file  does  not
              exist,  a  warning message will be displayed.  The file will not
              be created.

       -k file-name, --keyfile=file-name
              Look in this file for the key specified with -a.

              This option specifies the keyfile.  sntp will search for the key
              specified  with -a keyno in this file.  See ntp.keys(5) for more

       -l file-name, --logfile=file-name
              Log to specified logfile.

              This option causes the client to write log messages to the spec-
              ified logfile.

       -M number, --steplimit=number
              Adjustments  less  than  steplimit  msec  will  be slewed.  This
              option takes an integer number as its argument.   The  value  of
              number is constrained to being:
                  greater than or equal to 0

              If the time adjustment is less than steplimit milliseconds, slew
              the amount using adjtime(2).  Otherwise, step the correction
              using settimeofday(2).  The default value is 0, which means all
              adjustments will be stepped.  This is a feature, as different
              situations demand different values.

       -o number, --ntpversion=number
              Send int as our NTP protocol version.  This option takes an
              integer number as its argument.  The value of number is con-
              strained to being:
                  in the range  0 through 7
              The default number for this option is:

              When sending requests to a remote server, tell them we are run-
              ning NTP protocol version ntpversion .

       -r, --usereservedport
              Use the NTP Reserved Port (port 123).

              Use port 123, which is reserved for NTP, for our network commu-

       -S, --step
              OK to 'step' the time with settimeofday(2).

       -s, --slew
              OK to 'slew' the time with adjtime(2).

       -t seconds, --timeout=seconds
              The number of seconds to wait for responses.  This option takes
              an integer number as its argument.  The default seconds for this
              option is:

              When waiting for a reply, sntp will wait the number of seconds
              specified before giving up.  The default should be more than
              enough for a unicast response.  If sntp is only waiting for a
              broadcast response a longer timeout is likely needed.

       --wait, - Fl -no-wait
              Wait for pending replies (if not setting the time).  The no-wait
              form will disable the option.  This option is enabled by

              If we are not setting the time, wait for all pending responses.

       -?, --help
              Display usage information and exit.

       -!, --more-help
              Pass the extended usage information through a pager.

       -> [cfgfile], --save-opts [=cfgfile]
              Save the option state to cfgfile.  The default is the last con-
              figuration file listed in the OPTION PRESETS section, below.
              The command will exit after updating the config file.

       -<cfgfile, --load-opts=cfgfile, --no-load-opts
              Load options from cfgfile.  The no-load-opts form will disable
              the loading of earlier config/rc/ini files.  --no-load-opts is
              handled early, out of order.

       --version [{v|c|n}]
              Output version of program and exit.  The default mode is `v', a
              simple version.  The `c' mode will print copyright information
              and `n' will print the full copyright notice.

       Any option that is not marked as not presettable may be preset by load-
       ing values from configuration ("RC" or ".INI") file(s) and values from
       environment variables named:
         SNTP_<option-name> or SNTP
       The environmental presets take precedence (are  processed  later  than)
       the  configuration  files.   The homerc files are "$HOME", and ".".  If
       any of these are directories, then the  file  .ntprc  is  searched  for
       within those directories.

       sntp ntpserver.somewhere
              is the simplest use of this program and can be run as an unpriv-
              ileged command to check the current time and error in the  local

       sntp -Ss -M 128 ntpserver.somewhere
              With suitable privilege, run as a command or from a cron(8) job,
              sntp -Ss -M 128 ntpserver.somewhere will request the  time  from
              the  server,  and if that server reports that it is synchronized
              then if the offset adjustment is less than 128 milliseconds  the
              correction  will  be  slewed, and if the correction is more than
              128 milliseconds the correction  will be stepped.

       sntp -S ntpserver.somewhere
              With suitable privilege, run as a command or from a cron(8) job,
              sntp -S ntpserver.somewhere will set (step) the local clock from
              a synchronized specified  server,  like  the  (deprecated)  ntp-
              date(1), or rdate(8) commands.

       See OPTION PRESETS for configuration environment variables.

       See OPTION PRESETS for configuration files.

       One of the following exit values will be returned:

       0  (EXIT_SUCCESS)
              Successful program execution.

       1  (EXIT_FAILURE)
              The operation failed or the command syntax was not valid.

       66  (EX_NOINPUT)
              A specified configuration file could not be loaded.

       70  (EX_SOFTWARE)
              libopts  had an internal operational error.  Please report it to
      Thank you.

       Johannes Maximilian Kuehn
       Harlan Stenn
       Dave Hart

       Please send bug reports to:,