19c2daa00SOllivier Robert<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 29c2daa00SOllivier Robert 39c2daa00SOllivier Robert<html> 49c2daa00SOllivier Robert 59c2daa00SOllivier Robert <head> 69c2daa00SOllivier Robert <meta name="generator" content="HTML Tidy, see www.w3.org"> 79c2daa00SOllivier Robert <title>ntpdc - special NTP query program</title> 89c2daa00SOllivier Robert <link href="scripts/style.css" type="text/css" rel="stylesheet"> 99c2daa00SOllivier Robert </head> 109c2daa00SOllivier Robert 119c2daa00SOllivier Robert <body> 129c2daa00SOllivier Robert <h3><tt>ntpdc</tt> - special NTP query program</h3> 139c2daa00SOllivier Robert <img src="pic/alice31.gif" alt="gif" align="left"><a href="http://www.eecis.udel.edu/~mills/pictures.html">from <i>Alice's Adventures in Wonderland</i>, Lewis Carroll</a> 149c2daa00SOllivier Robert <p>This program is a big puppy.</p> 159c2daa00SOllivier Robert <p>Last update: <csobj format="ShortTime" h="24" locale="00000409" region="0" t="DateTime" w="50">21:39</csobj> UTC <csobj format="LongDate" h="24" locale="00000409" region="0" t="DateTime" w="230">Sunday, January 26, 2003</csobj></p> 169c2daa00SOllivier Robert <br clear="left"> 179c2daa00SOllivier Robert <h4>More Help</h4> 189c2daa00SOllivier Robert <script type="text/javascript" language="javascript" src="scripts/links12.txt"></script> 199c2daa00SOllivier Robert <hr> 209c2daa00SOllivier Robert <h4>Synopsis</h4> 219c2daa00SOllivier Robert <tt>ntpdc [ -ilnps ] [ -c <i>command</i> ] [ <i>host</i> ] [ ... ]</tt> 229c2daa00SOllivier Robert <h4>Description</h4> 239c2daa00SOllivier Robert <tt>ntpdc</tt> is used to query the <tt>ntpd</tt> daemon about its current state and to request changes in that state. The program may be run either in interactive mode or controlled using command line arguments. Extensive state and statistics information is available through the <tt>ntpdc</tt> interface. In addition, nearly all the configuration options which can be specified at startup using ntpd's configuration file may also be specified at run time using <tt>ntpdc</tt>. 249c2daa00SOllivier Robert <p>If one or more request options are included on the command line when <tt>ntpdc</tt> is executed, each of the requests will be sent to the NTP servers running on each of the hosts given as command line arguments, or on localhost by default. If no request options are given, <tt>ntpdc</tt> will attempt to read commands from the standard input and execute these on the NTP server running on the first host given on the command line, again defaulting to localhost when no other host is specified. <tt>ntpdc</tt> will prompt for commands if the standard input is a terminal device.</p> 259c2daa00SOllivier Robert <p><tt>ntpdc</tt> uses NTP mode 7 packets to communicate with the NTP server, and hence can be used to query any compatible server on the network which permits it. Note that since NTP is a UDP protocol this communication will be somewhat unreliable, especially over large distances in terms of network topology. <tt>ntpdc</tt> makes no attempt to retransmit requests, and will time requests out if the remote host is not heard from within a suitable timeout time.</p> 269c2daa00SOllivier Robert <p>The operation of <tt>ntpdc</tt> are specific to the particular implementation of the <tt>ntpd</tt> daemon and can be expected to work only with this and maybe some previous versions of the daemon. Requests from a remote <tt>ntpdc</tt> program which affect the state of the local server must be authenticated, which requires both the remote program and local server share a common key and key identifier.</p> 279c2daa00SOllivier Robert <p>Note that in contexts where a host name is expected, a <tt>-4</tt> qualifier preceding the host name forces DNS resolution to the IPv4 namespace, while a <tt>-6</tt> qualifier forces DNS resolution to the IPv6 namespace.</p> 289c2daa00SOllivier Robert <h4>Command Line Options</h4> 299c2daa00SOllivier Robert <p>Specifying a command line option other than <tt>-i</tt> or <tt>-n</tt> will cause the specified query (queries) to be sent to the indicated host(s) immediately. Otherwise, <tt>ntpdc</tt> will attempt to read interactive format commands from the standard input.</p> 309c2daa00SOllivier Robert <dl> 319c2daa00SOllivier Robert <dt><tt>-4</tt> 329c2daa00SOllivier Robert <dd>Force DNS resolution of following host names on the command line to the IPv4 namespace. 339c2daa00SOllivier Robert <dt><tt>-6</tt> 349c2daa00SOllivier Robert <dd>Force DNS resolution of following host names on the command line to the IPv6 namespace. 359c2daa00SOllivier Robert <dt><tt>-c <i>command</i></tt> 369c2daa00SOllivier Robert <dd>The following argument is interpreted as an interactive format command and is added to the list of commands to be executed on the specified host(s). Multiple -c options may be given. 379c2daa00SOllivier Robert <dt><tt>-i</tt> 389c2daa00SOllivier Robert <dd>Force <tt>ntpdc</tt> to operate in interactive mode. Prompts will be written to the standard output and commands read from the standard input. 399c2daa00SOllivier Robert <dt><tt>-l</tt> 409c2daa00SOllivier Robert <dd>Obtain a list of peers which are known to the server(s). This switch is equivalent to <tt>-c listpeers</tt>. 419c2daa00SOllivier Robert <dt><tt>-n</tt> 429c2daa00SOllivier Robert <dd>Output all host addresses in dotted-quad numeric format rather than converting to the canonical host names. 439c2daa00SOllivier Robert <dt><tt>-p</tt> 449c2daa00SOllivier Robert <dd>Print a list of the peers known to the server as well as a summary of their state. This is equivalent to <tt>-c peers</tt>. 459c2daa00SOllivier Robert <dt><tt>-s</tt> 469c2daa00SOllivier Robert <dd>Print a list of the peers known to the server as well as a summary of their state, but in a slightly different format than the -p switch. This is equivalent to <tt>-c dmpeers</tt>. 479c2daa00SOllivier Robert </dl> 489c2daa00SOllivier Robert <h4>Interactive Commands</h4> 499c2daa00SOllivier Robert <p>Interactive format commands consist of a keyword followed by zero to four arguments. Only enough characters of the full keyword to uniquely identify the command need be typed. The output of a command is normally sent to the standard output, but optionally the output of individual commands may be sent to a file by appending a <tt><</tt>, followed by a file name, to the command line.</p> 509c2daa00SOllivier Robert <p>A number of interactive format commands are executed entirely within the <tt>ntpdc</tt> program itself and do not result in NTP mode 7 requests being sent to a server. These are described following.</p> 519c2daa00SOllivier Robert <dl> 529c2daa00SOllivier Robert <dt><tt>? [ <i>command_keyword</i> ]</tt><br> 539c2daa00SOllivier Robert <tt>help [ <i>command_keyword</i> ]</tt> 549c2daa00SOllivier Robert <dd>A <tt>?</tt> by itself will print a list of all the command keywords known to this incarnation of <tt>ntpq</tt>. A <tt>?</tt> followed by a command keyword will print function and usage information about the command. This command is probably a better source of information about <tt>ntpq</tt> than this manual page. 559c2daa00SOllivier Robert <dt><tt>delay <i>milliseconds</i></tt> 569c2daa00SOllivier Robert <dd>Specify a time interval to be added to timestamps included in requests which require authentication. This is used to enable (unreliable) server reconfiguration over long delay network paths or between machines whose clocks are unsynchronized. Actually the server does not now require timestamps in authenticated requests, so this command may be obsolete. 579c2daa00SOllivier Robert <dt><tt>host <i>hostname</i></tt> 589c2daa00SOllivier Robert <dd>Set the host to which future queries will be sent. Hostname may be either a host name or a numeric address. 599c2daa00SOllivier Robert <dt><tt>hostnames [ yes | no ]</tt> 609c2daa00SOllivier Robert <dd>If <tt>yes</tt> is specified, host names are printed in information displays. If <tt>no</tt> is specified, numeric addresses are printed instead. The default is <tt>yes</tt>, unless modified using the command line <tt>-n</tt> switch. 619c2daa00SOllivier Robert <dt><tt>keyid <i>keyid</i></tt> 629c2daa00SOllivier Robert <dd>This command allows the specification of a key number to be used to authenticate configuration requests. This must correspond to a key number the server has been configured to use for this purpose. 639c2daa00SOllivier Robert <dt><tt>quit</tt> 649c2daa00SOllivier Robert <dd>Exit <tt>ntpdc</tt>. 659c2daa00SOllivier Robert <dt><tt>passwd</tt> 669c2daa00SOllivier Robert <dd>This command prompts you to type in a password (which will not be echoed) which will be used to authenticate configuration requests. The password must correspond to the key configured for use by the NTP server for this purpose if such requests are to be successful. 679c2daa00SOllivier Robert <dt><tt>timeout <i>millseconds</i></tt> 689c2daa00SOllivier Robert <dd>Specify a timeout period for responses to server queries. The default is about 8000 milliseconds. Note that since <tt>ntpdc</tt> retries each query once after a timeout, the total waiting time for a timeout will be twice the timeout value set. 699c2daa00SOllivier Robert </dl> 709c2daa00SOllivier Robert <h4>Control Message Commands</h4> 719c2daa00SOllivier Robert <p>Query commands result in NTP mode 7 packets containing requests for information being sent to the server. These are read-only commands in that they make no modification of the server configuration state.</p> 729c2daa00SOllivier Robert <dl> 739c2daa00SOllivier Robert <dt><tt>listpeers</tt> 749c2daa00SOllivier Robert <dd>Obtains and prints a brief list of the peers for which the server is maintaining state. These should include all configured peer associations as well as those peers whose stratum is such that they are considered by the server to be possible future synchronization candidates. 759c2daa00SOllivier Robert <dt><tt>peers</tt> 769c2daa00SOllivier Robert <dd>Obtains a list of peers for which the server is maintaining state, along with a summary of that state. Summary information includes the address of the remote peer, the local interface address (0.0.0.0 if a local address has yet to be determined), the stratum of the remote peer (a stratum of 16 indicates the remote peer is unsynchronized), the polling interval, in seconds, the reachability register, in octal, and the current estimated delay, offset and dispersion of the peer, all in seconds. 779c2daa00SOllivier Robert <p>The character in the left margin indicates the mode this peer entry is operating in. A <tt>+</tt> denotes symmetric active, a <tt>-</tt> indicates symmetric passive, a <tt>=</tt> means the remote server is being polled in client mode, a <tt>^</tt> indicates that the server is broadcasting to this address, a <tt>~</tt> denotes that the remote peer is sending broadcasts and a <tt>*</tt> marks the peer the server is currently synchronizing to.</p> 789c2daa00SOllivier Robert <p>The contents of the host field may be one of four forms. It may be a host name, an IP address, a reference clock implementation name with its parameter or <tt>REFCLK(<i>implementation number</i>, <i>parameter</i>)</tt>. On <tt>hostnames no</tt> only IP-addresses will be displayed.</p> 799c2daa00SOllivier Robert <dt><tt>dmpeers</tt> 809c2daa00SOllivier Robert <dd>A slightly different peer summary list. Identical to the output of the <tt>peers</tt> command, except for the character in the leftmost column. Characters only appear beside peers which were included in the final stage of the clock selection algorithm. A <tt>.</tt> indicates that this peer was cast off in the falseticker detection, while a <tt>+</tt> indicates that the peer made it through. A <tt>*</tt> denotes the peer the server is currently synchronizing with. 819c2daa00SOllivier Robert <dt><tt>showpeer <i>peer_address</i> [...]</tt> 829c2daa00SOllivier Robert <dd>Shows a detailed display of the current peer variables for one or more peers. Most of these values are described in the NTP Version 2 specification. 839c2daa00SOllivier Robert <dt><tt>pstats <i>peer_address</i> [...]</tt> 849c2daa00SOllivier Robert <dd>Show per-peer statistic counters associated with the specified peer(s). 859c2daa00SOllivier Robert <dt><tt>clockinfo <i>clock_peer_address</i> [...]</tt> 869c2daa00SOllivier Robert <dd>Obtain and print information concerning a peer clock. The values obtained provide information on the setting of fudge factors and other clock performance information. 879c2daa00SOllivier Robert <dt><tt>kerninfo</tt> 889c2daa00SOllivier Robert <dd>Obtain and print kernel phase-lock loop operating parameters. This information is available only if the kernel has been specially modified for a precision timekeeping function. 899c2daa00SOllivier Robert <dt><tt>loopinfo [ oneline | multiline ]</tt> 909c2daa00SOllivier Robert <dd>Print the values of selected loop filter variables. The loop filter is the part of NTP which deals with adjusting the local system clock. The <tt>offset</tt> is the last offset given to the loop filter by the packet processing code. The <tt>frequency</tt> is the frequency error of the local clock in parts-per-million (ppm). The <tt>time_const</tt> controls the stiffness of the phase-lock loop and thus the speed at which it can adapt to oscillator drift. The <tt>watchdog timer</tt> value is the number of seconds which have elapsed since the last sample offset was given to the loop filter. The <tt>oneline</tt> and <tt>multiline</tt> options specify the format in which this information is to be printed, with <tt>multiline</tt> as the default. 919c2daa00SOllivier Robert <dt><tt>sysinfo</tt> 929c2daa00SOllivier Robert <dd>Print a variety of system state variables, i.e., state related to the local server. All except the last four lines are described in the NTP Version 3 specification, RFC-1305. 939c2daa00SOllivier Robert <p>The <tt>system flags</tt> show various system flags, some of which can be set and cleared by the <tt>enable</tt> and <tt>disable</tt> configuration commands, respectively. These are the <tt>auth</tt>, <tt>bclient</tt>, <tt>monitor</tt>, <tt>pll</tt>, <tt>pps</tt> and <tt>stats</tt> flags. See the <tt>ntpd</tt> documentation for the meaning of these flags. There are two additional flags which are read only, the <tt>kernel_pll</tt> and <tt>kernel_pps</tt>. These flags indicate the synchronization status when the precision time kernel modifications are in use. The <tt>kernel_pll</tt> indicates that the local clock is being disciplined by the kernel, while the kernel_pps indicates the kernel discipline is provided by the PPS signal.</p> 949c2daa00SOllivier Robert <p>The <tt>stability</tt> is the residual frequency error remaining afterthe system frequency correction is applied and is intended for maintenance and debugging. In most architectures, this value will initially decrease from as high as 500 ppm to a nominal value in the range .01 to 0.1 ppm. If it remains high for some time after starting the daemon, something may be wrong with the local clock, or the value of the kernel variable <tt>tick</tt> may be incorrect.</p> 959c2daa00SOllivier Robert <p>The <tt>broadcastdelay</tt> shows the default broadcast delay, as set by the <tt>broadcastdelay</tt> configuration command.</p> 969c2daa00SOllivier Robert <p>The <tt>authdelay</tt> shows the default authentication delay, as set by the <tt>authdelay</tt> configuration command.</p> 979c2daa00SOllivier Robert <dt><tt>sysstats</tt> 989c2daa00SOllivier Robert <dd>Print statistics counters maintained in the protocol module. 999c2daa00SOllivier Robert <dt><tt>memstats</tt> 1009c2daa00SOllivier Robert <dd>Print statistics counters related to memory allocation code. 1019c2daa00SOllivier Robert <dt><tt>iostats</tt> 1029c2daa00SOllivier Robert <dd>Print statistics counters maintained in the input-output module. 1039c2daa00SOllivier Robert <dt><tt>timerstats</tt> 1049c2daa00SOllivier Robert <dd>Print statistics counters maintained in the timer/event queue support code. 1059c2daa00SOllivier Robert <dt><tt>reslist</tt> 1069c2daa00SOllivier Robert <dd>Obtain and print the server's restriction list. This list is (usually) printed in sorted order and may help to understand how the restrictions are applied. 1079c2daa00SOllivier Robert <dt><tt>monlist [ <i>version</i> ]</tt> 1089c2daa00SOllivier Robert <dd>Obtain and print traffic counts collected and maintained by the monitor facility. The version number should not normally need to be specified. 1099c2daa00SOllivier Robert <dt><tt>clkbug <i>clock_peer_address</i> [...]</tt> 1109c2daa00SOllivier Robert <dd>Obtain debugging information for a reference clock driver. This information is provided only by some clock drivers and is mostly undecodable without a copy of the driver source in hand. 1119c2daa00SOllivier Robert </dl> 1129c2daa00SOllivier Robert <h4>Runtime Configuration Requests</h4> 1139c2daa00SOllivier Robert <p>All requests which cause state changes in the server are authenticated by the server using a configured NTP key (the facility can also be disabled by the server by not configuring a key). The key number and the corresponding key must also be made known to <tt>ntpdc<\tt>. This can be done using the keyid and passwd commands, the latter of which will prompt at the terminal for a password to use as the encryption key. You will also be prompted automatically for both the key number and password the first time a command which would result in an authenticated request to the server is given. Authentication not only provides verification that the requester has permission to make such changes, but also gives an extra degree of protection again transmission errors.</p> 1149c2daa00SOllivier Robert <p>Authenticated requests always include a timestamp in the packet data, which is included in the computation of the authentication code. This timestamp is compared by the server to its receive time stamp. If they differ by more than a small amount the request is rejected. This is done for two reasons. First, it makes simple replay attacks on the server, by someone who might be able to overhear traffic on your LAN, much more difficult. Second, it makes it more difficult to request configuration changes to your server from topologically remote hosts. While the reconfiguration facility will work well with a server on the local host, and may work adequately between time-synchronized hosts on the same LAN, it will work very poorly for more distant hosts. As such, if reasonable passwords are chosen, care is taken in the distribution and protection of keys and appropriate source address restrictions are applied, the run time reconfiguration facility should provide an adequate level of security.</p> 1159c2daa00SOllivier Robert <p>The following commands all make authenticated requests.</p> 1169c2daa00SOllivier Robert <dl> 1179c2daa00SOllivier Robert <dt><tt>addpeer <i>peer_address</i> [ <i>keyid</i> ] [ <i>version</i> ] [ <i>prefer</i> ]</tt> 1189c2daa00SOllivier Robert <dd>Add a configured peer association at the given address and operating in symmetric active mode. Note that an existing association with the same peer may be deleted when this command is executed, or may simply be converted to conform to the new configuration, as appropriate. If the optional <tt>keyid</tt> is a nonzero integer, all outgoing packets to the remote server will have an authentication field attached encrypted with this key. If the value is 0 (or not given) no authentication will be done. The <tt>version#</tt> can be 1, 2 or 3 and defaults to 3. The <tt>prefer</tt> keyword indicates a preferred peer (and thus will be used primarily for clock synchronisation if possible). The preferred peer also determines the validity of the PPS signal - if the preferred peer is suitable for synchronisation so is the PPS signal. 1199c2daa00SOllivier Robert <dt><tt>addserver <i>peer_address</i> [ <i>keyid</i> ] [ <i>version</i> ] [ <i>prefer</i> ]</tt> 1209c2daa00SOllivier Robert <dd>Identical to the addpeer command, except that the operating mode is client. 1219c2daa00SOllivier Robert <dt><tt>broadcast <i>peer_address</i> [ <i>keyid</i> ] [ <i>version</i> ] [ <i>prefer</i> ]</tt> 1229c2daa00SOllivier Robert <dd>Identical to the addpeer command, except that the operating mode is broadcast. In this case a valid key identifier and key are required. The <tt>peer_address</tt> parameter can be the broadcast address of the local network or a multicast group address assigned to NTP. If a multicast address, a multicast-capable kernel is required. 1239c2daa00SOllivier Robert <dt><tt>unconfig <i>peer_address</i> [...]</tt> 1249c2daa00SOllivier Robert <dd>This command causes the configured bit to be removed from the specified peer(s). In many cases this will cause the peer association to be deleted. When appropriate, however, the association may persist in an unconfigured mode if the remote peer is willing to continue on in this fashion. 1259c2daa00SOllivier Robert <dt><tt>fudge <i>peer_address</i> [ <i>time1</i> ] [ <i>time2</i> ] [ <i>stratum</i> ] [ <i>refid</i> ]</tt> 1269c2daa00SOllivier Robert <dd>This command provides a way to set certain data for a reference clock. See the source listing for further information. 1279c2daa00SOllivier Robert <dt><tt>enable [ auth | bclient | calibrate | kernel | monitor | ntp | pps | stats]</tt><br> 1289c2daa00SOllivier Robert <tt>disable [ auth | bclient | calibrate | kernel | monitor | ntp | pps | stats]</tt> 1299c2daa00SOllivier Robert <dd>These commands operate in the same way as the <tt>enable</tt> and <tt>disable</tt> configuration file commands of <tt>ntpd</tt>. See the <a href="miscopt.html">Miscellaneous Options</a> page for further information. 1309c2daa00SOllivier Robert <dt><tt>restrict <i>address mask flag</i> [ <i>flag</i> ]</tt> 1319c2daa00SOllivier Robert <dd>This command operates in the same way as the <tt>restrict</tt> configuration file commands of <tt>ntpd</tt>. 1329c2daa00SOllivier Robert <dt><tt>unrestrict <i>address mask flag</i> [ <i>flag</i> ]</tt> 1339c2daa00SOllivier Robert <dd>Unrestrict the matching entry from the restrict list. 1349c2daa00SOllivier Robert <dt><tt>delrestrict <i>address mask [ ntpport ]</i></tt> 1359c2daa00SOllivier Robert <dd>Delete the matching entry from the restrict list. 1369c2daa00SOllivier Robert <dt><tt>readkeys</tt> 1379c2daa00SOllivier Robert <dd>Causes the current set of authentication keys to be purged and a new set to be obtained by rereading the keys file (which must have been specified in the <tt>ntpd</tt> configuration file). This allows encryption keys to be changed without restarting the server. 1389c2daa00SOllivier Robert <dt><tt>trustedkey <i>keyid</i> [...]</tt> 1399c2daa00SOllivier Robert <dt><tt>untrustedkey <i>keyid</i> [...]</tt> 1409c2daa00SOllivier Robert <dd>These commands operate in the same way as the <tt>trustedkey</tt> and <tt>untrustedkey</tt> configuration file commands of <tt>ntpd</tt>. 1419c2daa00SOllivier Robert <dt><tt>authinfo</tt> 1429c2daa00SOllivier Robert <dd>Returns information concerning the authentication module, including known keys and counts of encryptions and decryptions which have been done. 1439c2daa00SOllivier Robert <dt><tt>traps</tt> 1449c2daa00SOllivier Robert <dd>Display the traps set in the server. See the source listing for further information. 1459c2daa00SOllivier Robert <dt><tt>addtrap [ <i>address</i> [ <i>port</i> ] [ <i>interface</i> ]</tt> 1469c2daa00SOllivier Robert <dd>Set a trap for asynchronous messages. See the source listing for further information. 1479c2daa00SOllivier Robert <dt><tt>clrtrap [ <i>address</i> [ <i>port</i> ] [ <i>interface</i>]</tt> 1489c2daa00SOllivier Robert <dd>Clear a trap for asynchronous messages. See the source listing for further information. 1499c2daa00SOllivier Robert <dt><tt>reset</tt> 1509c2daa00SOllivier Robert <dd>Clear the statistics counters in various modules of the server. See the source listing for further information. 1519c2daa00SOllivier Robert </dl> 1529c2daa00SOllivier Robert <h4>Bugs</h4> 1539c2daa00SOllivier Robert <p><tt>ntpdc</tt> is a crude hack. Much of the information it shows is deadly boring and could only be loved by its implementer. The program was designed so that new (and temporary) features were easy to hack in, at great expense to the program's ease of use. Despite this, the program is occasionally useful.</p> 1549c2daa00SOllivier Robert <hr> 1559c2daa00SOllivier Robert <script type="text/javascript" language="javascript" src="scripts/footer.txt"></script> 1569c2daa00SOllivier Robert </body> 1579c2daa00SOllivier Robert 1589c2daa00SOllivier Robert</html> 159
