a25439b686
Reviewed by: delphij (suggested MFC) Approved by: roberto Security: CVE-2015-1798, CVE-2015-1799 Security: VuXML ebd84c96-dd7e-11e4-854e-3c970e169bc2 MFC after: 1 month
313 lines
11 KiB
Plaintext
313 lines
11 KiB
Plaintext
.Dd April 7 2015
|
|
.Dt SNTP 1sntpmdoc User Commands
|
|
.Os
|
|
.\" EDIT THIS FILE WITH CAUTION (sntp-opts.mdoc)
|
|
.\"
|
|
.\" It has been AutoGen-ed April 7, 2015 at 04:18:06 AM by AutoGen 5.18.5pre4
|
|
.\" From the definitions sntp-opts.def
|
|
.\" and the template file agmdoc-cmd.tpl
|
|
.Sh NAME
|
|
.Nm sntp
|
|
.Nd standard Simple Network Time Protocol client program
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.\" Mixture of short (flag) options and long options
|
|
.Op Fl flags
|
|
.Op Fl flag Op Ar value
|
|
.Op Fl \-option\-name Ns Oo Oo Ns "=| " Oc Ns Ar value Oc
|
|
[ hostname\-or\-IP ...]
|
|
.Pp
|
|
.Sh DESCRIPTION
|
|
.Nm
|
|
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
|
|
.Ic cron
|
|
job.
|
|
NTP (the Network Time Protocol) and SNTP (the Simple Network Time Protocol)
|
|
are defined and described by RFC 5905.
|
|
.Pp
|
|
The default is to write the estimated correct local date and time (i.e. not
|
|
UTC) to the standard output in a format like:
|
|
.Ic "'1996\-10\-15 20:17:25.123 (+0800) +4.567 +/\- 0.089 [host] IP sN'"
|
|
where the
|
|
.Ic "'(+0800)'"
|
|
means that to get to UTC from the reported local time one must
|
|
add 8 hours and 0 minutes,
|
|
the
|
|
.Ic "'+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.
|
|
.Ic "'+/\- 0.089'"
|
|
is the reported
|
|
.Em 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
|
|
synchronization distance, this will be reported as
|
|
.Ic "'+/\- ?'" .
|
|
If the
|
|
.Em host
|
|
is different from the
|
|
.Em IP ,
|
|
both will be displayed.
|
|
Otherwise, only the
|
|
.Em IP
|
|
is displayed.
|
|
Finally, the
|
|
.Em stratum
|
|
of the host is reported
|
|
and the leap indicator is decoded and displayed.
|
|
.Sh "OPTIONS"
|
|
.Bl -tag
|
|
.It Fl 4 , Fl \-ipv4
|
|
Force IPv4 DNS name resolution.
|
|
This option must not appear in combination with any of the following options:
|
|
ipv6.
|
|
.sp
|
|
Force DNS resolution of the following host names on the command line
|
|
to the IPv4 namespace.
|
|
.It Fl 6 , Fl \-ipv6
|
|
Force IPv6 DNS name resolution.
|
|
This option must not appear in combination with any of the following options:
|
|
ipv4.
|
|
.sp
|
|
Force DNS resolution of the following host names on the command line
|
|
to the IPv6 namespace.
|
|
.It Fl a Ar auth\-keynumber , Fl \-authentication Ns = Ns Ar auth\-keynumber
|
|
Enable authentication with the key \fBauth\-keynumber\fP.
|
|
This option takes an integer number as its argument.
|
|
.sp
|
|
Enable authentication using the key specified in this option's
|
|
argument. The argument of this option is the \fBkeyid\fP, a
|
|
number specified in the \fBkeyfile\fP as this key's identifier.
|
|
See the \fBkeyfile\fP option (\fB\-k\fP) for more details.
|
|
.It Fl b Ar broadcast\-address , Fl \-broadcast Ns = Ns Ar broadcast\-address
|
|
Listen to the address specified for broadcast time sync.
|
|
This option may appear an unlimited number of times.
|
|
.sp
|
|
If specified \fBsntp\fP will listen to the specified address
|
|
for NTP broadcasts. The default maximum wait time
|
|
can (and probably should) be modified with \fB\-t\fP.
|
|
.It Fl c Ar host\-name , Fl \-concurrent Ns = Ns Ar host\-name
|
|
Concurrently query all IPs returned for host\-name.
|
|
This option may appear an unlimited number of times.
|
|
.sp
|
|
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
|
|
\fBntpd\fP, and therefore \fBsntp\fP will send queries to these IPs
|
|
one after another, with a 2\-second gap in between each query.
|
|
.sp
|
|
The \fB\-c\fP or \fB\-\-concurrent\fP 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.
|
|
.It Fl d , Fl \-debug\-level
|
|
Increase debug verbosity level.
|
|
This option may appear an unlimited number of times.
|
|
.sp
|
|
.It Fl D Ar number , Fl \-set\-debug\-level Ns = Ns Ar number
|
|
Set the debug verbosity level.
|
|
This option may appear an unlimited number of times.
|
|
This option takes an integer number as its argument.
|
|
.sp
|
|
.It Fl g Ar milliseconds , Fl \-gap Ns = Ns Ar milliseconds
|
|
The gap (in milliseconds) between time requests.
|
|
This option takes an integer number as its argument.
|
|
The default
|
|
.Ar milliseconds
|
|
for this option is:
|
|
.ti +4
|
|
50
|
|
.sp
|
|
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.
|
|
.It Fl K Ar file\-name , Fl \-kod Ns = Ns Ar file\-name
|
|
KoD history filename.
|
|
The default
|
|
.Ar file\-name
|
|
for this option is:
|
|
.ti +4
|
|
/var/db/ntp\-kod
|
|
.sp
|
|
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.
|
|
.It Fl k Ar file\-name , Fl \-keyfile Ns = Ns Ar file\-name
|
|
Look in this file for the key specified with \fB\-a\fP.
|
|
.sp
|
|
This option specifies the keyfile.
|
|
\fBsntp\fP will search for the key specified with \fB\-a\fP
|
|
\fIkeyno\fP in this file. See \fBntp.keys(5)\fP for more
|
|
information.
|
|
.It Fl l Ar file\-name , Fl \-logfile Ns = Ns Ar file\-name
|
|
Log to specified logfile.
|
|
.sp
|
|
This option causes the client to write log messages to the specified
|
|
\fIlogfile\fP.
|
|
.It Fl M Ar number , Fl \-steplimit Ns = Ns Ar number
|
|
Adjustments less than \fBsteplimit\fP msec will be slewed.
|
|
This option takes an integer number as its argument.
|
|
The value of
|
|
.Ar number
|
|
is constrained to being:
|
|
.in +4
|
|
.nf
|
|
.na
|
|
greater than or equal to 0
|
|
.fi
|
|
.in -4
|
|
.sp
|
|
If the time adjustment is less than \fIsteplimit\fP milliseconds,
|
|
slew the amount using \fBadjtime(2)\fP. Otherwise, step the
|
|
correction using \fBsettimeofday(2)\fP. The default value is 0,
|
|
which means all adjustments will be stepped. This is a feature, as
|
|
different situations demand different values.
|
|
.It Fl o Ar number , Fl \-ntpversion Ns = Ns Ar number
|
|
Send \fBint\fP as our NTP protocol version.
|
|
This option takes an integer number as its argument.
|
|
The value of
|
|
.Ar number
|
|
is constrained to being:
|
|
.in +4
|
|
.nf
|
|
.na
|
|
in the range 0 through 7
|
|
.fi
|
|
.in -4
|
|
The default
|
|
.Ar number
|
|
for this option is:
|
|
.ti +4
|
|
4
|
|
.sp
|
|
When sending requests to a remote server, tell them we are running
|
|
NTP protocol version \fIntpversion\fP .
|
|
.It Fl r , Fl \-usereservedport
|
|
Use the NTP Reserved Port (port 123).
|
|
.sp
|
|
Use port 123, which is reserved for NTP, for our network
|
|
communications.
|
|
.It Fl S , Fl \-step
|
|
OK to 'step' the time with \fBsettimeofday(2)\fP.
|
|
.sp
|
|
.It Fl s , Fl \-slew
|
|
OK to 'slew' the time with \fBadjtime(2)\fP.
|
|
.sp
|
|
.It Fl t Ar seconds , Fl \-timeout Ns = Ns Ar seconds
|
|
The number of seconds to wait for responses.
|
|
This option takes an integer number as its argument.
|
|
The default
|
|
.Ar seconds
|
|
for this option is:
|
|
.ti +4
|
|
5
|
|
.sp
|
|
When waiting for a reply, \fBsntp\fP will wait the number
|
|
of seconds specified before giving up. The default should be
|
|
more than enough for a unicast response. If \fBsntp\fP is
|
|
only waiting for a broadcast response a longer timeout is
|
|
likely needed.
|
|
.It Fl \-wait , " Fl \-no\-wait"
|
|
Wait for pending replies (if not setting the time).
|
|
The \fIno\-wait\fP form will disable the option.
|
|
This option is enabled by default.
|
|
.sp
|
|
If we are not setting the time, wait for all pending responses.
|
|
.It Fl \&? , Fl \-help
|
|
Display usage information and exit.
|
|
.It Fl \&! , Fl \-more\-help
|
|
Pass the extended usage information through a pager.
|
|
.It Fl > Oo Ar cfgfile Oc , Fl \-save\-opts Oo Ns = Ns Ar cfgfile Oc
|
|
Save the option state to \fIcfgfile\fP. The default is the \fIlast\fP
|
|
configuration file listed in the \fBOPTION PRESETS\fP section, below.
|
|
The command will exit after updating the config file.
|
|
.It Fl < Ar cfgfile , Fl \-load\-opts Ns = Ns Ar cfgfile , Fl \-no\-load\-opts
|
|
Load options from \fIcfgfile\fP.
|
|
The \fIno\-load\-opts\fP form will disable the loading
|
|
of earlier config/rc/ini files. \fI\-\-no\-load\-opts\fP is handled early,
|
|
out of order.
|
|
.It Fl \-version Op Brq Ar 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.
|
|
.El
|
|
.Sh "OPTION PRESETS"
|
|
Any option that is not marked as \fInot presettable\fP may be preset
|
|
by loading values from configuration ("RC" or ".INI") file(s) and values from
|
|
environment variables named:
|
|
.nf
|
|
\fBSNTP_<option\-name>\fP or \fBSNTP\fP
|
|
.fi
|
|
.ad
|
|
The environmental presets take precedence (are processed later than)
|
|
the configuration files.
|
|
The \fIhomerc\fP files are "\fI$HOME\fP", and "\fI.\fP".
|
|
If any of these are directories, then the file \fI.ntprc\fP
|
|
is searched for within those directories.
|
|
.Sh USAGE
|
|
.Bl -tag -width indent
|
|
.It Li "sntp ntpserver.somewhere"
|
|
is the simplest use of this program
|
|
and can be run as an unprivileged command
|
|
to check the current time and error in the local clock.
|
|
.It Li "sntp \-Ss \-M 128 ntpserver.somewhere"
|
|
With suitable privilege,
|
|
run as a command
|
|
or from a
|
|
.Xr cron 8
|
|
job,
|
|
.Ic "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.
|
|
.It Li "sntp \-S ntpserver.somewhere"
|
|
With suitable privilege,
|
|
run as a command
|
|
or from a
|
|
.Xr cron 8
|
|
job,
|
|
.Ic "sntp \-S ntpserver.somewhere"
|
|
will set (step) the local clock from a synchronized specified server,
|
|
like the (deprecated)
|
|
.Xr ntpdate 1ntpdatemdoc ,
|
|
or
|
|
.Xr rdate 8
|
|
commands.
|
|
.El
|
|
.Sh "ENVIRONMENT"
|
|
See \fBOPTION PRESETS\fP for configuration environment variables.
|
|
.Sh "FILES"
|
|
See \fBOPTION PRESETS\fP for configuration files.
|
|
.Sh "EXIT STATUS"
|
|
One of the following exit values will be returned:
|
|
.Bl -tag
|
|
.It 0 " (EXIT_SUCCESS)"
|
|
Successful program execution.
|
|
.It 1 " (EXIT_FAILURE)"
|
|
The operation failed or the command syntax was not valid.
|
|
.It 66 " (EX_NOINPUT)"
|
|
A specified configuration file could not be loaded.
|
|
.It 70 " (EX_SOFTWARE)"
|
|
libopts had an internal operational error. Please report
|
|
it to autogen\-users@lists.sourceforge.net. Thank you.
|
|
.El
|
|
.Sh AUTHORS
|
|
.An "Johannes Maximilian Kuehn"
|
|
.An "Harlan Stenn"
|
|
.An "Dave Hart"
|
|
.Sh "COPYRIGHT"
|
|
Copyright (C) 1992\-2015 The University of Delaware and Network Time Foundation all rights reserved.
|
|
This program is released under the terms of the NTP license, <http://ntp.org/license>.
|
|
.Sh "BUGS"
|
|
Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org
|
|
.Sh "NOTES"
|
|
This manual page was \fIAutoGen\fP\-erated from the \fBsntp\fP
|
|
option definitions.
|