sntp.1sntpmdoc revision 1.1.1.2.4.2
1 1.1.1.2.4.2 snj .Dd December 19 2014 2 1.1.1.2.4.2 snj .Dt SNTP 1sntpmdoc User Commands 3 1.1.1.2.4.2 snj .Os 4 1.1.1.2.4.2 snj .\" EDIT THIS FILE WITH CAUTION (sntp-opts.mdoc) 5 1.1.1.2.4.2 snj .\" 6 1.1.1.2.4.2 snj .\" It has been AutoGen-ed December 19, 2014 at 07:51:38 AM by AutoGen 5.18.5pre4 7 1.1.1.2.4.2 snj .\" From the definitions sntp-opts.def 8 1.1.1.2.4.2 snj .\" and the template file agmdoc-cmd.tpl 9 1.1.1.2.4.2 snj .Sh NAME 10 1.1.1.2.4.2 snj .Nm sntp 11 1.1.1.2.4.2 snj .Nd standard Simple Network Time Protocol client program 12 1.1.1.2.4.2 snj .Sh SYNOPSIS 13 1.1.1.2.4.2 snj .Nm 14 1.1.1.2.4.2 snj .\" Mixture of short (flag) options and long options 15 1.1.1.2.4.2 snj .Op Fl flags 16 1.1.1.2.4.2 snj .Op Fl flag Op Ar value 17 1.1.1.2.4.2 snj .Op Fl \-option\-name Ns Oo Oo Ns "=| " Oc Ns Ar value Oc 18 1.1.1.2.4.2 snj [ hostname\-or\-IP ...] 19 1.1.1.2.4.2 snj .Pp 20 1.1.1.2.4.2 snj .Sh DESCRIPTION 21 1.1.1.2.4.2 snj .Nm 22 1.1.1.2.4.2 snj can be used as an SNTP client to query a NTP or SNTP server and either display 23 1.1.1.2.4.2 snj the time or set the local system's time (given suitable privilege). It can be 24 1.1.1.2.4.2 snj run as an interactive command or from a 25 1.1.1.2.4.2 snj .Ic cron 26 1.1.1.2.4.2 snj job. 27 1.1.1.2.4.2 snj NTP (the Network Time Protocol) and SNTP (the Simple Network Time Protocol) 28 1.1.1.2.4.2 snj are defined and described by RFC 5905. 29 1.1.1.2.4.2 snj .Pp 30 1.1.1.2.4.2 snj The default is to write the estimated correct local date and time (i.e. not 31 1.1.1.2.4.2 snj UTC) to the standard output in a format like: 32 1.1.1.2.4.2 snj .Ic "'1996\-10\-15 20:17:25.123 (+0800) +4.567 +/\- 0.089 [host] IP sN'" 33 1.1.1.2.4.2 snj where the 34 1.1.1.2.4.2 snj .Ic "'(+0800)'" 35 1.1.1.2.4.2 snj means that to get to UTC from the reported local time one must 36 1.1.1.2.4.2 snj add 8 hours and 0 minutes, 37 1.1.1.2.4.2 snj the 38 1.1.1.2.4.2 snj .Ic "'+4.567'" 39 1.1.1.2.4.2 snj indicates the local clock is 4.567 seconds behind the correct time 40 1.1.1.2.4.2 snj (so 4.567 seconds must be added to the local clock to get it to be correct). 41 1.1.1.2.4.2 snj Note that the number of decimals printed for this value will change 42 1.1.1.2.4.2 snj based on the reported precision of the server. 43 1.1.1.2.4.2 snj .Ic "'+/\- 0.089'" 44 1.1.1.2.4.2 snj is the reported 45 1.1.1.2.4.2 snj .Em synchronization distance 46 1.1.1.2.4.2 snj (in seconds), which represents the maximum error due to all causes. 47 1.1.1.2.4.2 snj If the server does not report valid data needed to calculate the 48 1.1.1.2.4.2 snj synchronization distance, this will be reported as 49 1.1.1.2.4.2 snj .Ic "'+/\- ?'" . 50 1.1.1.2.4.2 snj If the 51 1.1.1.2.4.2 snj .Em host 52 1.1.1.2.4.2 snj is different from the 53 1.1.1.2.4.2 snj .Em IP , 54 1.1.1.2.4.2 snj both will be displayed. 55 1.1.1.2.4.2 snj Otherwise, only the 56 1.1.1.2.4.2 snj .Em IP 57 1.1.1.2.4.2 snj is displayed. 58 1.1.1.2.4.2 snj Finally, the 59 1.1.1.2.4.2 snj .Em stratum 60 1.1.1.2.4.2 snj of the host is reported. 61 1.1.1.2.4.2 snj .Sh "OPTIONS" 62 1.1.1.2.4.2 snj .Bl -tag 63 1.1.1.2.4.2 snj .It Fl 4 , Fl \-ipv4 64 1.1.1.2.4.2 snj Force IPv4 DNS name resolution. 65 1.1.1.2.4.2 snj This option must not appear in combination with any of the following options: 66 1.1.1.2.4.2 snj ipv6. 67 1.1.1.2.4.2 snj .sp 68 1.1.1.2.4.2 snj Force DNS resolution of the following host names on the command line 69 1.1.1.2.4.2 snj to the IPv4 namespace. 70 1.1.1.2.4.2 snj .It Fl 6 , Fl \-ipv6 71 1.1.1.2.4.2 snj Force IPv6 DNS name resolution. 72 1.1.1.2.4.2 snj This option must not appear in combination with any of the following options: 73 1.1.1.2.4.2 snj ipv4. 74 1.1.1.2.4.2 snj .sp 75 1.1.1.2.4.2 snj Force DNS resolution of the following host names on the command line 76 1.1.1.2.4.2 snj to the IPv6 namespace. 77 1.1.1.2.4.2 snj .It Fl a Ar auth\-keynumber , Fl \-authentication Ns = Ns Ar auth\-keynumber 78 1.1.1.2.4.2 snj Enable authentication with the key \fBauth\-keynumber\fP. 79 1.1.1.2.4.2 snj This option takes an integer number as its argument. 80 1.1.1.2.4.2 snj .sp 81 1.1.1.2.4.2 snj Enable authentication using the key specified in this option's 82 1.1.1.2.4.2 snj argument. The argument of this option is the \fBkeyid\fP, a 83 1.1.1.2.4.2 snj number specified in the \fBkeyfile\fP as this key's identifier. 84 1.1.1.2.4.2 snj See the \fBkeyfile\fP option (\fB\-k\fP) for more details. 85 1.1.1.2.4.2 snj .It Fl b Ar broadcast\-address , Fl \-broadcast Ns = Ns Ar broadcast\-address 86 1.1.1.2.4.2 snj Listen to the address specified for broadcast time sync. 87 1.1.1.2.4.2 snj This option may appear an unlimited number of times. 88 1.1.1.2.4.2 snj .sp 89 1.1.1.2.4.2 snj If specified \fBsntp\fP will listen to the specified address 90 1.1.1.2.4.2 snj for NTP broadcasts. The default maximum wait time 91 1.1.1.2.4.2 snj can (and probably should) be modified with \fB\-t\fP. 92 1.1.1.2.4.2 snj .It Fl c Ar host\-name , Fl \-concurrent Ns = Ns Ar host\-name 93 1.1.1.2.4.2 snj Concurrently query all IPs returned for host\-name. 94 1.1.1.2.4.2 snj This option may appear an unlimited number of times. 95 1.1.1.2.4.2 snj .sp 96 1.1.1.2.4.2 snj Requests from an NTP "client" to a "server" should never be sent 97 1.1.1.2.4.2 snj more rapidly than one every 2 seconds. By default, any IPs returned 98 1.1.1.2.4.2 snj as part of a DNS lookup are assumed to be for a single instance of 99 1.1.1.2.4.2 snj \fBntpd\fP, and therefore \fBsntp\fP will send queries to these IPs 100 1.1.1.2.4.2 snj one after another, with a 2\-second gap in between each query. 101 1.1.1.2.4.2 snj .sp 102 1.1.1.2.4.2 snj The \fB\-c\fP or \fB\-\-concurrent\fP flag says that any IPs 103 1.1.1.2.4.2 snj returned for the DNS lookup of the supplied host\-name are on 104 1.1.1.2.4.2 snj different machines, so we can send concurrent queries. 105 1.1.1.2.4.2 snj .It Fl d , Fl \-debug\-level 106 1.1.1.2.4.2 snj Increase debug verbosity level. 107 1.1.1.2.4.2 snj This option may appear an unlimited number of times. 108 1.1.1.2.4.2 snj .sp 109 1.1.1.2.4.2 snj .It Fl D Ar number , Fl \-set\-debug\-level Ns = Ns Ar number 110 1.1.1.2.4.2 snj Set the debug verbosity level. 111 1.1.1.2.4.2 snj This option may appear an unlimited number of times. 112 1.1.1.2.4.2 snj This option takes an integer number as its argument. 113 1.1.1.2.4.2 snj .sp 114 1.1.1.2.4.2 snj .It Fl g Ar milliseconds , Fl \-gap Ns = Ns Ar milliseconds 115 1.1.1.2.4.2 snj The gap (in milliseconds) between time requests. 116 1.1.1.2.4.2 snj This option takes an integer number as its argument. 117 1.1.1.2.4.2 snj The default 118 1.1.1.2.4.2 snj .Ar milliseconds 119 1.1.1.2.4.2 snj for this option is: 120 1.1.1.2.4.2 snj .ti +4 121 1.1.1.2.4.2 snj 50 122 1.1.1.2.4.2 snj .sp 123 1.1.1.2.4.2 snj Since we're only going to use the first valid response we get and 124 1.1.1.2.4.2 snj there is benefit to specifying a good number of servers to query, 125 1.1.1.2.4.2 snj separate the queries we send out by the specified number of 126 1.1.1.2.4.2 snj milliseconds. 127 1.1.1.2.4.2 snj .It Fl K Ar file\-name , Fl \-kod Ns = Ns Ar file\-name 128 1.1.1.2.4.2 snj KoD history filename. 129 1.1.1.2.4.2 snj The default 130 1.1.1.2.4.2 snj .Ar file\-name 131 1.1.1.2.4.2 snj for this option is: 132 1.1.1.2.4.2 snj .ti +4 133 1.1.1.2.4.2 snj /var/db/ntp\-kod 134 1.1.1.2.4.2 snj .sp 135 1.1.1.2.4.2 snj Specifies the filename to be used for the persistent history of KoD 136 1.1.1.2.4.2 snj responses received from servers. If the file does not exist, a 137 1.1.1.2.4.2 snj warning message will be displayed. The file will not be created. 138 1.1.1.2.4.2 snj .It Fl k Ar file\-name , Fl \-keyfile Ns = Ns Ar file\-name 139 1.1.1.2.4.2 snj Look in this file for the key specified with \fB\-a\fP. 140 1.1.1.2.4.2 snj .sp 141 1.1.1.2.4.2 snj This option specifies the keyfile. 142 1.1.1.2.4.2 snj \fBsntp\fP will search for the key specified with \fB\-a\fP 143 1.1.1.2.4.2 snj \fIkeyno\fP in this file. See \fBntp.keys(5)\fP for more 144 1.1.1.2.4.2 snj information. 145 1.1.1.2.4.2 snj .It Fl l Ar file\-name , Fl \-logfile Ns = Ns Ar file\-name 146 1.1.1.2.4.2 snj Log to specified logfile. 147 1.1.1.2.4.2 snj .sp 148 1.1.1.2.4.2 snj This option causes the client to write log messages to the specified 149 1.1.1.2.4.2 snj \fIlogfile\fP. 150 1.1.1.2.4.2 snj .It Fl M Ar number , Fl \-steplimit Ns = Ns Ar number 151 1.1.1.2.4.2 snj Adjustments less than \fBsteplimit\fP msec will be slewed. 152 1.1.1.2.4.2 snj This option takes an integer number as its argument. 153 1.1.1.2.4.2 snj The value of 154 1.1.1.2.4.2 snj .Ar number 155 1.1.1.2.4.2 snj is constrained to being: 156 1.1.1.2.4.2 snj .in +4 157 1.1.1.2.4.2 snj .nf 158 1.1.1.2.4.2 snj .na 159 1.1.1.2.4.2 snj greater than or equal to 0 160 1.1.1.2.4.2 snj .fi 161 1.1.1.2.4.2 snj .in -4 162 1.1.1.2.4.2 snj .sp 163 1.1.1.2.4.2 snj If the time adjustment is less than \fIsteplimit\fP milliseconds, 164 1.1.1.2.4.2 snj slew the amount using \fBadjtime(2)\fP. Otherwise, step the 165 1.1.1.2.4.2 snj correction using \fBsettimeofday(2)\fP. 166 1.1.1.2.4.2 snj .It Fl o Ar number , Fl \-ntpversion Ns = Ns Ar number 167 1.1.1.2.4.2 snj Send \fBint\fP as our NTP protocol version. 168 1.1.1.2.4.2 snj This option takes an integer number as its argument. 169 1.1.1.2.4.2 snj The value of 170 1.1.1.2.4.2 snj .Ar number 171 1.1.1.2.4.2 snj is constrained to being: 172 1.1.1.2.4.2 snj .in +4 173 1.1.1.2.4.2 snj .nf 174 1.1.1.2.4.2 snj .na 175 1.1.1.2.4.2 snj in the range 0 through 7 176 1.1.1.2.4.2 snj .fi 177 1.1.1.2.4.2 snj .in -4 178 1.1.1.2.4.2 snj The default 179 1.1.1.2.4.2 snj .Ar number 180 1.1.1.2.4.2 snj for this option is: 181 1.1.1.2.4.2 snj .ti +4 182 1.1.1.2.4.2 snj 4 183 1.1.1.2.4.2 snj .sp 184 1.1.1.2.4.2 snj When sending requests to a remote server, tell them we are running 185 1.1.1.2.4.2 snj NTP protocol version \fIntpversion\fP . 186 1.1.1.2.4.2 snj .It Fl r , Fl \-usereservedport 187 1.1.1.2.4.2 snj Use the NTP Reserved Port (port 123). 188 1.1.1.2.4.2 snj .sp 189 1.1.1.2.4.2 snj Use port 123, which is reserved for NTP, for our network 190 1.1.1.2.4.2 snj communications. 191 1.1.1.2.4.2 snj .It Fl S , Fl \-step 192 1.1.1.2.4.2 snj OK to 'step' the time with \fBsettimeofday(2)\fP. 193 1.1.1.2.4.2 snj .sp 194 1.1.1.2.4.2 snj .It Fl s , Fl \-slew 195 1.1.1.2.4.2 snj OK to 'slew' the time with \fBadjtime(2)\fP. 196 1.1.1.2.4.2 snj .sp 197 1.1.1.2.4.2 snj .It Fl t Ar seconds , Fl \-timeout Ns = Ns Ar seconds 198 1.1.1.2.4.2 snj The number of seconds to wait for responses. 199 1.1.1.2.4.2 snj This option takes an integer number as its argument. 200 1.1.1.2.4.2 snj The default 201 1.1.1.2.4.2 snj .Ar seconds 202 1.1.1.2.4.2 snj for this option is: 203 1.1.1.2.4.2 snj .ti +4 204 1.1.1.2.4.2 snj 5 205 1.1.1.2.4.2 snj .sp 206 1.1.1.2.4.2 snj When waiting for a reply, \fBsntp\fP will wait the number 207 1.1.1.2.4.2 snj of seconds specified before giving up. The default should be 208 1.1.1.2.4.2 snj more than enough for a unicast response. If \fBsntp\fP is 209 1.1.1.2.4.2 snj only waiting for a broadcast response a longer timeout is 210 1.1.1.2.4.2 snj likely needed. 211 1.1.1.2.4.2 snj .It Fl \-wait , " Fl \-no\-wait" 212 1.1.1.2.4.2 snj Wait for pending replies (if not setting the time). 213 1.1.1.2.4.2 snj The \fIno\-wait\fP form will disable the option. 214 1.1.1.2.4.2 snj This option is enabled by default. 215 1.1.1.2.4.2 snj .sp 216 1.1.1.2.4.2 snj If we are not setting the time, wait for all pending responses. 217 1.1.1.2.4.2 snj .It Fl \&? , Fl \-help 218 1.1.1.2.4.2 snj Display usage information and exit. 219 1.1.1.2.4.2 snj .It Fl \&! , Fl \-more\-help 220 1.1.1.2.4.2 snj Pass the extended usage information through a pager. 221 1.1.1.2.4.2 snj .It Fl > Oo Ar cfgfile Oc , Fl \-save\-opts Oo Ns = Ns Ar cfgfile Oc 222 1.1.1.2.4.2 snj Save the option state to \fIcfgfile\fP. The default is the \fIlast\fP 223 1.1.1.2.4.2 snj configuration file listed in the \fBOPTION PRESETS\fP section, below. 224 1.1.1.2.4.2 snj The command will exit after updating the config file. 225 1.1.1.2.4.2 snj .It Fl < Ar cfgfile , Fl \-load\-opts Ns = Ns Ar cfgfile , Fl \-no\-load\-opts 226 1.1.1.2.4.2 snj Load options from \fIcfgfile\fP. 227 1.1.1.2.4.2 snj The \fIno\-load\-opts\fP form will disable the loading 228 1.1.1.2.4.2 snj of earlier config/rc/ini files. \fI\-\-no\-load\-opts\fP is handled early, 229 1.1.1.2.4.2 snj out of order. 230 1.1.1.2.4.2 snj .It Fl \-version Op Brq Ar v|c|n 231 1.1.1.2.4.2 snj Output version of program and exit. The default mode is `v', a simple 232 1.1.1.2.4.2 snj version. The `c' mode will print copyright information and `n' will 233 1.1.1.2.4.2 snj print the full copyright notice. 234 1.1.1.2.4.2 snj .El 235 1.1.1.2.4.2 snj .Sh "OPTION PRESETS" 236 1.1.1.2.4.2 snj Any option that is not marked as \fInot presettable\fP may be preset 237 1.1.1.2.4.2 snj by loading values from configuration ("RC" or ".INI") file(s) and values from 238 1.1.1.2.4.2 snj environment variables named: 239 1.1.1.2.4.2 snj .nf 240 1.1.1.2.4.2 snj \fBSNTP_<option\-name>\fP or \fBSNTP\fP 241 1.1.1.2.4.2 snj .fi 242 1.1.1.2.4.2 snj .ad 243 1.1.1.2.4.2 snj The environmental presets take precedence (are processed later than) 244 1.1.1.2.4.2 snj the configuration files. 245 1.1.1.2.4.2 snj The \fIhomerc\fP files are "\fI$HOME\fP", and "\fI.\fP". 246 1.1.1.2.4.2 snj If any of these are directories, then the file \fI.ntprc\fP 247 1.1.1.2.4.2 snj is searched for within those directories. 248 1.1.1.2.4.2 snj .Sh USAGE 249 1.1.1.2.4.2 snj .Bl -tag -width indent 250 1.1.1.2.4.2 snj .It Li "sntp ntpserver.somewhere" 251 1.1.1.2.4.2 snj is the simplest use of this program 252 1.1.1.2.4.2 snj and can be run as an unprivileged command 253 1.1.1.2.4.2 snj to check the current time and error in the local clock. 254 1.1.1.2.4.2 snj .It Li "sntp \-a ntpserver.somewhere" 255 1.1.1.2.4.2 snj With suitable privilege, 256 1.1.1.2.4.2 snj run as a command 257 1.1.1.2.4.2 snj or from a 258 1.1.1.2.4.2 snj .Xr cron 8 259 1.1.1.2.4.2 snj job, 260 1.1.1.2.4.2 snj .Ic "sntp \-a" 261 1.1.1.2.4.2 snj will reset the local clock from a synchronized specified server, 262 1.1.1.2.4.2 snj like the (deprecated) 263 1.1.1.2.4.2 snj .Xr ntpdate 1ntpdatemdoc , 264 1.1.1.2.4.2 snj or 265 1.1.1.2.4.2 snj .Xr rdate 8 266 1.1.1.2.4.2 snj commands. 267 1.1.1.2.4.2 snj .El 268 1.1.1.2.4.2 snj .Sh "ENVIRONMENT" 269 1.1.1.2.4.2 snj See \fBOPTION PRESETS\fP for configuration environment variables. 270 1.1.1.2.4.2 snj .Sh "FILES" 271 1.1.1.2.4.2 snj See \fBOPTION PRESETS\fP for configuration files. 272 1.1.1.2.4.2 snj .Sh "EXIT STATUS" 273 1.1.1.2.4.2 snj One of the following exit values will be returned: 274 1.1.1.2.4.2 snj .Bl -tag 275 1.1.1.2.4.2 snj .It 0 " (EXIT_SUCCESS)" 276 1.1.1.2.4.2 snj Successful program execution. 277 1.1.1.2.4.2 snj .It 1 " (EXIT_FAILURE)" 278 1.1.1.2.4.2 snj The operation failed or the command syntax was not valid. 279 1.1.1.2.4.2 snj .It 66 " (EX_NOINPUT)" 280 1.1.1.2.4.2 snj A specified configuration file could not be loaded. 281 1.1.1.2.4.2 snj .It 70 " (EX_SOFTWARE)" 282 1.1.1.2.4.2 snj libopts had an internal operational error. Please report 283 1.1.1.2.4.2 snj it to autogen\-users (a] lists.sourceforge.net. Thank you. 284 1.1.1.2.4.2 snj .El 285 1.1.1.2.4.2 snj .Sh AUTHORS 286 1.1.1.2.4.2 snj .An "Johannes Maximilian Kuehn" 287 1.1.1.2.4.2 snj .An "Harlan Stenn" 288 1.1.1.2.4.2 snj .An "Dave Hart" 289 1.1.1.2.4.2 snj .Sh "COPYRIGHT" 290 1.1.1.2.4.2 snj Copyright (C) 1970\-2014 The University of Delaware all rights reserved. 291 1.1.1.2.4.2 snj This program is released under the terms of the NTP license, <http://ntp.org/license>. 292 1.1.1.2.4.2 snj .Sh "BUGS" 293 1.1.1.2.4.2 snj Please send bug reports to: http://bugs.ntp.org, bugs (a] ntp.org 294 1.1.1.2.4.2 snj .Sh "NOTES" 295 1.1.1.2.4.2 snj This manual page was \fIAutoGen\fP\-erated from the \fBsntp\fP 296 1.1.1.2.4.2 snj option definitions. 297
Indexes created Mon Aug 24 00:24:59 UTC 2026