invoke-ntpd.texi revision 330106
1@node ntpd Invocation 2@section Invoking ntpd 3@pindex ntpd 4@cindex NTP daemon program 5@ignore 6# 7# EDIT THIS FILE WITH CAUTION (invoke-ntpd.texi) 8# 9# It has been AutoGen-ed February 27, 2018 at 05:14:39 PM by AutoGen 5.18.5 10# From the definitions ntpd-opts.def 11# and the template file agtexi-cmd.tpl 12@end ignore 13 14 15 16The 17@code{ntpd} 18utility is an operating system daemon which sets 19and maintains the system time of day in synchronism with Internet 20standard time servers. 21It is a complete implementation of the 22Network Time Protocol (NTP) version 4, as defined by RFC-5905, 23but also retains compatibility with 24version 3, as defined by RFC-1305, and versions 1 25and 2, as defined by RFC-1059 and RFC-1119, respectively. 26 27The 28@code{ntpd} 29utility does most computations in 64-bit floating point 30arithmetic and does relatively clumsy 64-bit fixed point operations 31only when necessary to preserve the ultimate precision, about 232 32picoseconds. 33While the ultimate precision is not achievable with 34ordinary workstations and networks of today, it may be required 35with future gigahertz CPU clocks and gigabit LANs. 36 37Ordinarily, 38@code{ntpd} 39reads the 40@code{ntp.conf(5)} 41configuration file at startup time in order to determine the 42synchronization sources and operating modes. 43It is also possible to 44specify a working, although limited, configuration entirely on the 45command line, obviating the need for a configuration file. 46This may 47be particularly useful when the local host is to be configured as a 48broadcast/multicast client, with all peers being determined by 49listening to broadcasts at run time. 50 51If NetInfo support is built into 52@code{ntpd} 53then 54@code{ntpd} 55will attempt to read its configuration from the 56NetInfo if the default 57@code{ntp.conf(5)} 58file cannot be read and no file is 59specified by the 60@code{-c} 61option. 62 63Various internal 64@code{ntpd} 65variables can be displayed and 66configuration options altered while the 67@code{ntpd} 68is running 69using the 70@code{ntpq(1ntpqmdoc)} 71and 72@code{ntpdc(1ntpdcmdoc)} 73utility programs. 74 75When 76@code{ntpd} 77starts it looks at the value of 78@code{umask(2)}, 79and if zero 80@code{ntpd} 81will set the 82@code{umask(2)} 83to 022. 84 85This section was generated by @strong{AutoGen}, 86using the @code{agtexi-cmd} template and the option descriptions for the @code{ntpd} program. 87This software is released under the NTP license, <http://ntp.org/license>. 88 89@menu 90* ntpd usage:: ntpd help/usage (@option{--help}) 91* ntpd ipv4:: ipv4 option (-4) 92* ntpd ipv6:: ipv6 option (-6) 93* ntpd authreq:: authreq option (-a) 94* ntpd authnoreq:: authnoreq option (-A) 95* ntpd configfile:: configfile option (-c) 96* ntpd driftfile:: driftfile option (-f) 97* ntpd panicgate:: panicgate option (-g) 98* ntpd force-step-once:: force-step-once option (-G) 99* ntpd jaildir:: jaildir option (-i) 100* ntpd interface:: interface option (-I) 101* ntpd keyfile:: keyfile option (-k) 102* ntpd logfile:: logfile option (-l) 103* ntpd novirtualips:: novirtualips option (-L) 104* ntpd modifymmtimer:: modifymmtimer option (-M) 105* ntpd nice:: nice option (-N) 106* ntpd pidfile:: pidfile option (-p) 107* ntpd priority:: priority option (-P) 108* ntpd quit:: quit option (-q) 109* ntpd propagationdelay:: propagationdelay option (-r) 110* ntpd saveconfigquit:: saveconfigquit option 111* ntpd statsdir:: statsdir option (-s) 112* ntpd trustedkey:: trustedkey option (-t) 113* ntpd user:: user option (-u) 114* ntpd updateinterval:: updateinterval option (-U) 115* ntpd wait-sync:: wait-sync option (-w) 116* ntpd slew:: slew option (-x) 117* ntpd usepcc:: usepcc option 118* ntpd pccfreq:: pccfreq option 119* ntpd mdns:: mdns option (-m) 120* ntpd config:: presetting/configuring ntpd 121* ntpd exit status:: exit status 122* ntpd Usage:: Usage 123* ntpd Files:: Files 124* ntpd See Also:: See Also 125* ntpd Bugs:: Bugs 126* ntpd Notes:: Notes 127@end menu 128 129@node ntpd usage 130@subsection ntpd help/usage (@option{--help}) 131@cindex ntpd help 132 133This is the automatically generated usage text for ntpd. 134 135The text printed is the same whether selected with the @code{help} option 136(@option{--help}) or the @code{more-help} option (@option{--more-help}). @code{more-help} will print 137the usage text by passing it through a pager program. 138@code{more-help} is disabled on platforms without a working 139@code{fork(2)} function. The @code{PAGER} environment variable is 140used to select the program, defaulting to @file{more}. Both will exit 141with a status code of 0. 142 143@exampleindent 0 144@example 145ntpd - NTP daemon program - Ver. 4.2.8p11 146Usage: ntpd [ -<flag> [<val>] | --<name>[@{=| @}<val>] ]... \ 147 [ <server1> ... <serverN> ] 148 Flg Arg Option-Name Description 149 -4 no ipv4 Force IPv4 DNS name resolution 150 - prohibits the option 'ipv6' 151 -6 no ipv6 Force IPv6 DNS name resolution 152 - prohibits the option 'ipv4' 153 -a no authreq Require crypto authentication 154 - prohibits the option 'authnoreq' 155 -A no authnoreq Do not require crypto authentication 156 - prohibits the option 'authreq' 157 -b no bcastsync Allow us to sync to broadcast servers 158 -c Str configfile configuration file name 159 -d no debug-level Increase debug verbosity level 160 - may appear multiple times 161 -D Num set-debug-level Set the debug verbosity level 162 - may appear multiple times 163 -f Str driftfile frequency drift file name 164 -g no panicgate Allow the first adjustment to be Big 165 - may appear multiple times 166 -G no force-step-once Step any initial offset correction. 167 -i Str jaildir Jail directory 168 -I Str interface Listen on an interface name or address 169 - may appear multiple times 170 -k Str keyfile path to symmetric keys 171 -l Str logfile path to the log file 172 -L no novirtualips Do not listen to virtual interfaces 173 -n no nofork Do not fork 174 - prohibits the option 'wait-sync' 175 -N no nice Run at high priority 176 -p Str pidfile path to the PID file 177 -P Num priority Process priority 178 -q no quit Set the time and quit 179 - prohibits these options: 180 saveconfigquit 181 wait-sync 182 -r Str propagationdelay Broadcast/propagation delay 183 Str saveconfigquit Save parsed configuration and quit 184 - prohibits these options: 185 quit 186 wait-sync 187 -s Str statsdir Statistics file location 188 -t Str trustedkey Trusted key number 189 - may appear multiple times 190 -u Str user Run as userid (or userid:groupid) 191 -U Num updateinterval interval in seconds between scans for new or dropped interfaces 192 Str var make ARG an ntp variable (RW) 193 - may appear multiple times 194 Str dvar make ARG an ntp variable (RW|DEF) 195 - may appear multiple times 196 -w Num wait-sync Seconds to wait for first clock sync 197 - prohibits these options: 198 nofork 199 quit 200 saveconfigquit 201 -x no slew Slew up to 600 seconds 202 opt version output version information and exit 203 -? no help display extended usage information and exit 204 -! no more-help extended usage information passed thru pager 205 206Options are specified by doubled hyphens and their name or by a single 207hyphen and the flag character. 208 209 210The following option preset mechanisms are supported: 211 - examining environment variables named NTPD_* 212 213Please send bug reports to: <http://bugs.ntp.org, bugs@@ntp.org> 214@end example 215@exampleindent 4 216 217@node ntpd ipv4 218@subsection ipv4 option (-4) 219@cindex ntpd-ipv4 220 221This is the ``force ipv4 dns name resolution'' option. 222 223@noindent 224This option has some usage constraints. It: 225@itemize @bullet 226@item 227must not appear in combination with any of the following options: 228ipv6. 229@end itemize 230 231Force DNS resolution of following host names on the command line 232to the IPv4 namespace. 233@node ntpd ipv6 234@subsection ipv6 option (-6) 235@cindex ntpd-ipv6 236 237This is the ``force ipv6 dns name resolution'' option. 238 239@noindent 240This option has some usage constraints. It: 241@itemize @bullet 242@item 243must not appear in combination with any of the following options: 244ipv4. 245@end itemize 246 247Force DNS resolution of following host names on the command line 248to the IPv6 namespace. 249@node ntpd authreq 250@subsection authreq option (-a) 251@cindex ntpd-authreq 252 253This is the ``require crypto authentication'' option. 254 255@noindent 256This option has some usage constraints. It: 257@itemize @bullet 258@item 259must not appear in combination with any of the following options: 260authnoreq. 261@end itemize 262 263Require cryptographic authentication for broadcast client, 264multicast client and symmetric passive associations. 265This is the default. 266@node ntpd authnoreq 267@subsection authnoreq option (-A) 268@cindex ntpd-authnoreq 269 270This is the ``do not require crypto authentication'' option. 271 272@noindent 273This option has some usage constraints. It: 274@itemize @bullet 275@item 276must not appear in combination with any of the following options: 277authreq. 278@end itemize 279 280Do not require cryptographic authentication for broadcast client, 281multicast client and symmetric passive associations. 282This is almost never a good idea. 283@node ntpd configfile 284@subsection configfile option (-c) 285@cindex ntpd-configfile 286 287This is the ``configuration file name'' option. 288This option takes a string argument. 289The name and path of the configuration file, 290@file{/etc/ntp.conf} 291by default. 292@node ntpd driftfile 293@subsection driftfile option (-f) 294@cindex ntpd-driftfile 295 296This is the ``frequency drift file name'' option. 297This option takes a string argument. 298The name and path of the frequency file, 299@file{/etc/ntp.drift} 300by default. 301This is the same operation as the 302@code{driftfile} @kbd{driftfile} 303configuration specification in the 304@file{/etc/ntp.conf} 305file. 306@node ntpd panicgate 307@subsection panicgate option (-g) 308@cindex ntpd-panicgate 309 310This is the ``allow the first adjustment to be big'' option. 311 312@noindent 313This option has some usage constraints. It: 314@itemize @bullet 315@item 316may appear an unlimited number of times. 317@end itemize 318 319Normally, 320@code{ntpd} 321exits with a message to the system log if the offset exceeds the panic threshold, which is 1000 s by default. This option allows the time to be set to any value without restriction; however, this can happen only once. If the threshold is exceeded after that, 322@code{ntpd} 323will exit with a message to the system log. This option can be used with the 324@code{-q} 325and 326@code{-x} 327options. 328See the 329@code{tinker} 330configuration file directive for other options. 331@node ntpd force-step-once 332@subsection force-step-once option (-G) 333@cindex ntpd-force-step-once 334 335This is the ``step any initial offset correction.'' option. 336Normally, 337@code{ntpd} 338steps the time if the time offset exceeds the step threshold, 339which is 128 ms by default, and otherwise slews the time. 340This option forces the initial offset correction to be stepped, 341so the highest time accuracy can be achieved quickly. 342However, this may also cause the time to be stepped back 343so this option must not be used if 344applications requiring monotonic time are running. 345See the @code{tinker} configuration file directive for other options. 346@node ntpd jaildir 347@subsection jaildir option (-i) 348@cindex ntpd-jaildir 349 350This is the ``jail directory'' option. 351This option takes a string argument. 352 353@noindent 354This option has some usage constraints. It: 355@itemize @bullet 356@item 357must be compiled in by defining @code{HAVE_DROPROOT} during the compilation. 358@end itemize 359 360Chroot the server to the directory 361@kbd{jaildir} 362. 363This option also implies that the server attempts to drop root privileges at startup. 364You may need to also specify a 365@code{-u} 366option. 367This option is only available if the OS supports adjusting the clock 368without full root privileges. 369This option is supported under NetBSD (configure with 370@code{--enable-clockctl}) or Linux (configure with 371@code{--enable-linuxcaps}) or Solaris (configure with @code{--enable-solarisprivs}). 372@node ntpd interface 373@subsection interface option (-I) 374@cindex ntpd-interface 375 376This is the ``listen on an interface name or address'' option. 377This option takes a string argument @file{iface}. 378 379@noindent 380This option has some usage constraints. It: 381@itemize @bullet 382@item 383may appear an unlimited number of times. 384@end itemize 385 386Open the network address given, or all the addresses associated with the 387given interface name. This option may appear multiple times. This option 388also implies not opening other addresses, except wildcard and localhost. 389This option is deprecated. Please consider using the configuration file 390@code{interface} command, which is more versatile. 391@node ntpd keyfile 392@subsection keyfile option (-k) 393@cindex ntpd-keyfile 394 395This is the ``path to symmetric keys'' option. 396This option takes a string argument. 397Specify the name and path of the symmetric key file. 398@file{/etc/ntp.keys} 399is the default. 400This is the same operation as the 401@code{keys} @kbd{keyfile} 402configuration file directive. 403@node ntpd logfile 404@subsection logfile option (-l) 405@cindex ntpd-logfile 406 407This is the ``path to the log file'' option. 408This option takes a string argument. 409Specify the name and path of the log file. 410The default is the system log file. 411This is the same operation as the 412@code{logfile} @kbd{logfile} 413configuration file directive. 414@node ntpd novirtualips 415@subsection novirtualips option (-L) 416@cindex ntpd-novirtualips 417 418This is the ``do not listen to virtual interfaces'' option. 419Do not listen to virtual interfaces, defined as those with 420names containing a colon. This option is deprecated. Please 421consider using the configuration file @code{interface} command, which 422is more versatile. 423@node ntpd modifymmtimer 424@subsection modifymmtimer option (-M) 425@cindex ntpd-modifymmtimer 426 427This is the ``modify multimedia timer (windows only)'' option. 428 429@noindent 430This option has some usage constraints. It: 431@itemize @bullet 432@item 433must be compiled in by defining @code{SYS_WINNT} during the compilation. 434@end itemize 435 436Set the Windows Multimedia Timer to highest resolution. This 437ensures the resolution does not change while ntpd is running, 438avoiding timekeeping glitches associated with changes. 439@node ntpd nice 440@subsection nice option (-N) 441@cindex ntpd-nice 442 443This is the ``run at high priority'' option. 444To the extent permitted by the operating system, run 445@code{ntpd} 446at the highest priority. 447@node ntpd pidfile 448@subsection pidfile option (-p) 449@cindex ntpd-pidfile 450 451This is the ``path to the pid file'' option. 452This option takes a string argument. 453Specify the name and path of the file used to record 454@code{ntpd}'s 455process ID. 456This is the same operation as the 457@code{pidfile} @kbd{pidfile} 458configuration file directive. 459@node ntpd priority 460@subsection priority option (-P) 461@cindex ntpd-priority 462 463This is the ``process priority'' option. 464This option takes a number argument. 465To the extent permitted by the operating system, run 466@code{ntpd} 467at the specified 468@code{sched_setscheduler(SCHED_FIFO)} 469priority. 470@node ntpd quit 471@subsection quit option (-q) 472@cindex ntpd-quit 473 474This is the ``set the time and quit'' option. 475 476@noindent 477This option has some usage constraints. It: 478@itemize @bullet 479@item 480must not appear in combination with any of the following options: 481saveconfigquit, wait-sync. 482@end itemize 483 484@code{ntpd} 485will not daemonize and will exit after the clock is first 486synchronized. This behavior mimics that of the 487@code{ntpdate} 488program, which will soon be replaced with a shell script. 489The 490@code{-g} 491and 492@code{-x} 493options can be used with this option. 494Note: The kernel time discipline is disabled with this option. 495@node ntpd propagationdelay 496@subsection propagationdelay option (-r) 497@cindex ntpd-propagationdelay 498 499This is the ``broadcast/propagation delay'' option. 500This option takes a string argument. 501Specify the default propagation delay from the broadcast/multicast server to this client. This is necessary only if the delay cannot be computed automatically by the protocol. 502@node ntpd saveconfigquit 503@subsection saveconfigquit option 504@cindex ntpd-saveconfigquit 505 506This is the ``save parsed configuration and quit'' option. 507This option takes a string argument. 508 509@noindent 510This option has some usage constraints. It: 511@itemize @bullet 512@item 513must be compiled in by defining @code{SAVECONFIG} during the compilation. 514@item 515must not appear in combination with any of the following options: 516quit, wait-sync. 517@end itemize 518 519Cause @code{ntpd} to parse its startup configuration file and save an 520equivalent to the given filename and exit. This option was 521designed for automated testing. 522@node ntpd statsdir 523@subsection statsdir option (-s) 524@cindex ntpd-statsdir 525 526This is the ``statistics file location'' option. 527This option takes a string argument. 528Specify the directory path for files created by the statistics facility. 529This is the same operation as the 530@code{statsdir} @kbd{statsdir} 531configuration file directive. 532@node ntpd trustedkey 533@subsection trustedkey option (-t) 534@cindex ntpd-trustedkey 535 536This is the ``trusted key number'' option. 537This option takes a string argument @file{tkey}. 538 539@noindent 540This option has some usage constraints. It: 541@itemize @bullet 542@item 543may appear an unlimited number of times. 544@end itemize 545 546Add the specified key number to the trusted key list. 547@node ntpd user 548@subsection user option (-u) 549@cindex ntpd-user 550 551This is the ``run as userid (or userid:groupid)'' option. 552This option takes a string argument. 553 554@noindent 555This option has some usage constraints. It: 556@itemize @bullet 557@item 558must be compiled in by defining @code{HAVE_DROPROOT} during the compilation. 559@end itemize 560 561Specify a user, and optionally a group, to switch to. 562This option is only available if the OS supports adjusting the clock 563without full root privileges. 564This option is supported under NetBSD (configure with 565@code{--enable-clockctl}) or Linux (configure with 566@code{--enable-linuxcaps}) or Solaris (configure with @code{--enable-solarisprivs}). 567@node ntpd updateinterval 568@subsection updateinterval option (-U) 569@cindex ntpd-updateinterval 570 571This is the ``interval in seconds between scans for new or dropped interfaces'' option. 572This option takes a number argument. 573Give the time in seconds between two scans for new or dropped interfaces. 574For systems with routing socket support the scans will be performed shortly after the interface change 575has been detected by the system. 576Use 0 to disable scanning. 60 seconds is the minimum time between scans. 577@node ntpd wait-sync 578@subsection wait-sync option (-w) 579@cindex ntpd-wait-sync 580 581This is the ``seconds to wait for first clock sync'' option. 582This option takes a number argument. 583 584@noindent 585This option has some usage constraints. It: 586@itemize @bullet 587@item 588must be compiled in by defining @code{HAVE_WORKING_FORK} during the compilation. 589@item 590must not appear in combination with any of the following options: 591nofork, quit, saveconfigquit. 592@end itemize 593 594If greater than zero, alters @code{ntpd}'s behavior when forking to 595daemonize. Instead of exiting with status 0 immediately after 596the fork, the parent waits up to the specified number of 597seconds for the child to first synchronize the clock. The exit 598status is zero (success) if the clock was synchronized, 599otherwise it is @code{ETIMEDOUT}. 600This provides the option for a script starting @code{ntpd} to easily 601wait for the first set of the clock before proceeding. 602@node ntpd slew 603@subsection slew option (-x) 604@cindex ntpd-slew 605 606This is the ``slew up to 600 seconds'' option. 607Normally, the time is slewed if the offset is less than the step threshold, which is 128 ms by default, and stepped if above the threshold. 608This option sets the threshold to 600 s, which is well within the accuracy window to set the clock manually. 609Note: Since the slew rate of typical Unix kernels is limited to 0.5 ms/s, each second of adjustment requires an amortization interval of 2000 s. 610Thus, an adjustment as much as 600 s will take almost 14 days to complete. 611This option can be used with the 612@code{-g} 613and 614@code{-q} 615options. 616See the 617@code{tinker} 618configuration file directive for other options. 619Note: The kernel time discipline is disabled with this option. 620@node ntpd usepcc 621@subsection usepcc option 622@cindex ntpd-usepcc 623 624This is the ``use cpu cycle counter (windows only)'' option. 625 626@noindent 627This option has some usage constraints. It: 628@itemize @bullet 629@item 630must be compiled in by defining @code{SYS_WINNT} during the compilation. 631@end itemize 632 633Attempt to substitute the CPU counter for @code{QueryPerformanceCounter}. 634The CPU counter and @code{QueryPerformanceCounter} are compared, and if 635they have the same frequency, the CPU counter (RDTSC on x86) is 636used directly, saving the overhead of a system call. 637@node ntpd pccfreq 638@subsection pccfreq option 639@cindex ntpd-pccfreq 640 641This is the ``force cpu cycle counter use (windows only)'' option. 642This option takes a string argument. 643 644@noindent 645This option has some usage constraints. It: 646@itemize @bullet 647@item 648must be compiled in by defining @code{SYS_WINNT} during the compilation. 649@end itemize 650 651Force substitution the CPU counter for @code{QueryPerformanceCounter}. 652The CPU counter (RDTSC on x86) is used unconditionally with the 653given frequency (in Hz). 654@node ntpd mdns 655@subsection mdns option (-m) 656@cindex ntpd-mdns 657 658This is the ``register with mdns as a ntp server'' option. 659 660@noindent 661This option has some usage constraints. It: 662@itemize @bullet 663@item 664must be compiled in by defining @code{HAVE_DNSREGISTRATION} during the compilation. 665@end itemize 666 667Registers as an NTP server with the local mDNS server which allows 668the server to be discovered via mDNS client lookup. 669 670 671@node ntpd config 672@subsection presetting/configuring ntpd 673 674Any option that is not marked as @i{not presettable} may be preset by 675loading values from environment variables named @code{NTPD} and @code{NTPD_<OPTION_NAME>}. @code{<OPTION_NAME>} must be one of 676the options listed above in upper case and segmented with underscores. 677The @code{NTPD} variable will be tokenized and parsed like 678the command line. The remaining variables are tested for existence and their 679values are treated like option arguments. 680 681 682The command line options relating to configuration and/or usage help are: 683 684@subsubheading version (-) 685 686Print the program version to standard out, optionally with licensing 687information, then exit 0. The optional argument specifies how much licensing 688detail to provide. The default is to print just the version. The licensing infomation may be selected with an option argument. 689Only the first letter of the argument is examined: 690 691@table @samp 692@item version 693Only print the version. This is the default. 694@item copyright 695Name the copyright usage licensing terms. 696@item verbose 697Print the full copyright usage licensing terms. 698@end table 699 700@node ntpd exit status 701@subsection ntpd exit status 702 703One of the following exit values will be returned: 704@table @samp 705@item 0 (EXIT_SUCCESS) 706Successful program execution. 707@item 1 (EXIT_FAILURE) 708The operation failed or the command syntax was not valid. 709@end table 710@node ntpd Usage 711@subsection ntpd Usage 712@node ntpd Files 713@subsection ntpd Files 714@node ntpd See Also 715@subsection ntpd See Also 716@node ntpd Bugs 717@subsection ntpd Bugs 718@node ntpd Notes 719@subsection ntpd Notes 720