ntpq



ntpq(1)                                                                ntpq(1)




NAME

       ntpq - standard NTP query program


SYNOPSIS

       ntpq [-inp] [-c command ] [ host ] [...]


DESCRIPTION

       The  ntpq  utility program is used to query NTP servers which implement
       the recommended NTP mode 6 control message format about  current  state
       and  to request changes in that state. The program may be run either in
       interactive mode or controlled using command line  arguments.  Requests
       to  read  and  write arbitrary variables can be assembled, with raw and
       pretty-printed output options being available.  ntpq  can  also  obtain
       and  print  a  list  of  peers  in  a common format by sending multiple
       queries to the server.

       If one or more request options is included on  the  command  line  when
       ntpq  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, ntpq  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.   ntpq
       will prompt for commands if the standard input is a terminal device.


       ntpq   uses  NTP mode 6 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.  ntpq  makes one attempt to retransmit requests,
       and will time requests out if the remote host is not heard from  within
       a suitable timeout time.

       Command line options are described following. Specifying a command line
       option other than -i  or -n  will cause the specified  query  (queries)
       to  be sent to the indicated host(s) immediately. Otherwise, ntpq  will
       attempt to read interactive format commands from the standard input.


       -c      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.

       -i      Force ntpq  to operate in interactive  mode.  Prompts  will  be
               written to the standard output and commands read from the stan-
               dard input.

       -n      Output all host addresses in dotted-quad numeric format  rather
               than converting to the canonical host names.

       -p      Print a list of the peers known to the server as well as a sum-
               mary of their state. This is equivalent to the  peers  interac-
               tive command.


INTERNAL COMMANDS

       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 < , followed by a file
       name, to the command line. A number of interactive format commands  are
       executed  entirely within the ntpq  program itself and do not result in
       NTP mode 6 requests being sent to a server. These are described follow-
       ing.


       ? [     command_keyword ]

               helpl  [  command_keyword ] A ?  by itself will print a list of
               all the command keywords known to this incarnation of ntpq .  A
               ?  followed  by a command keyword will print function and usage
               information about the command. This command is probably a  bet-
               ter source of information about ntpq  than this manual page.

       addvars variable_name  [ = value ] [...]

               rmvars variable_name  [...]

               clearvars The data carried by NTP mode 6 messages consists of a
               list of items of the form variable_name  = value  , where the =
               value    is  ignored,  and  can  be omitted, in requests to the
               server to read variables.  ntpq maintains an internal  list  in
               which data to be included in control messages can be assembled,
               and sent using the readlist  and writelist  commands  described
               below.  The addvars command allows variables and their optional
               values to be added to the list. If more than one variable is to
               be  added,  the  list should be comma-separated and not contain
               white space. The rmvars command can be used to remove  individ-
               ual  variables  from  the  list,  while  the clearlist  command
               removes all variables from the list.

       authenticate yes | no
               Normally ntpq  does not authenticate requests unless  they  are
               write  requests.  The  command authenticate yes causes ntpq  to
               send authentication with all requests it  makes.  Authenticated
               requests  causes  some servers to handle requests slightly dif-
               ferently, and can occasionally melt the CPU in fuzzballs if you
               turn  authentication on before doing a peer  display. [I didn’t
               know that - Ed.]

       cooked  Causes output from query commands to be "cooked", so that vari-
               ables  which  are  recognized  by  ntpq  will have their values
               reformatted for human consumption. Variables which ntpq  thinks
               should  have  a  decodable  value  but didn’t are marked with a
               trailing ? .

       debug more | less | off
               Turns internal query program debugging on and off.

       delay   milliseconds 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 unsynchro-
               nized. Actually the server does not now require  timestamps  in
               authenticated requests, so this command may be obsolete.

       host    hostname  Set  the  host  to which future queries will be sent.
               Hostname may be either a host name or a numeric address.

       hostnames [yes | no]
               If yes  is specified, host names  are  printed  in  information
               displays.  If  no   is specified, numeric addresses are printed
               instead. The default is yes , unless modified using the command
               line -n  switch.

       keyid   keyid  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.

       ntpversion 1 | 2 | 3 | 4
               Sets the NTP version number  which  ntpq   claims  in  packets.
               Defaults  to  3,  Note that mode 6 control messages (and modes,
               for that matter) didn’t exist in NTP version 1. There appear to
               be no servers left which demand version 1.

       quit    Exit ntpq .

       passwd  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.

       raw     Causes  all  output  from query commands is printed as received
               from the remote server. The only formating/interpretation  done
               on the data is to transform nonascii data into a printable (but
               barely understandable) form.

       timeout millseconds Specify a timeout period for  responses  to  server
               queries.  The  default  is  about  5000 milliseconds. Note that
               since ntpq retries each query once after a timeout,  the  total
               waiting time for a timeout will be twice the timeout value set.


CONTROL MESSAGE COMMANDS

       Each peer known to an NTP server has a 16 bit integer association iden-
       tifier  assigned to it. NTP control messages which carry peer variables
       must identify the peer the values correspond to by including its  asso-
       ciation  ID. An association ID of 0 is special, and indicates the vari-
       ables are system variables, whose names are drawn from a separate  name
       space.

       Control  message  commands  result  in  one or more NTP mode 6 messages
       being sent to the server, and cause the data returned to be printed  in
       some  format. Most commands currently implemented send a single message
       and expect a single response. The current exceptions are the peers com-
       mand,  which will send a preprogrammed series of messages to obtain the
       data it needs, and the mreadlist  and  mreadvar  commands,  which  will
       iterate over a range of associations.


       associations
               Obtains  and  prints a list of association identifiers and peer
               statuses for in-spec peers of the  server  being  queried.  The
               list is printed in columns. The first of these is an index num-
               bering the associations from 1 for internal use, the second the
               actual  association  identifier  returned by the server and the
               third the status word for the peer. This is followed by a  num-
               ber of columns containing data decoded from the status word See
               the peers command for a decode of the  condition   field.  Note
               that  the data returned by the associations"  command is cached
               internally in ntpq . The index is then of use when dealing with
               stupid servers which use association identifiers which are hard
               for humans to type, in that for any subsequent  commands  which
               require  an association identifier as an argument, the form and
               index may be used as an alternative.

       clockvar [
               assocID ] [ variable_name  [ = value  [...]] [...]

       cv [    assocID ] [ variable_name  [ =  value  [...]  ][...]   Requests
               that  a  list of the server’s clock variables be sent.  Servers
               which have a radio clock or other external synchronization will
               respond  positively  to  this. If the association identifier is
               omitted or zero the request is for the variables of the  system
               clock   and  will  generally  get  a positive response from all
               servers with a clock. If the server treats  clocks  as  pseudo-
               peers,  and  hence  can  possibly have more than one clock con-
               nected at once, referencing the appropriate peer association ID
               will  show  the  variables  of a particular clock. Omitting the
               variable list will cause the server to return a  default  vari-
               able display.

       lassocations
               Obtains  and  prints a list of association identifiers and peer
               statuses for all associations for which the server is maintain-
               ing  state. This command differs from the associations  command
               only for servers which  retain  state  for  out-of-spec  client
               associations  (i.e., fuzzballs). Such associations are normally
               omitted from the display  when  the  associations   command  is
               used, but are included in the output of lassociations .

       lpassociations
               Print  data  for all associations, including out-of-spec client
               associations, from the internally cached list of  associations.
               This command differs from passociations  only when dealing with
               fuzzballs.

       lpeers  Like R peers, except a summary of all  associations  for  which
               the  server is maintaining state is printed. This can produce a
               much longer list of peers from fuzzball servers.

       mreadlist
               assocID assocID

               mrl assocID assocID Like  the  readlist   command,  except  the
               query is done for each of a range of (nonzero) association IDs.
               This range is determined from the association  list  cached  by
               the most recent associations  command.

       mreadvar
               assocID assocID  [ variable_name  [ = value [ ... ]

               mrv  assocID  assocID   [ variable_name  [ = value [ ... ] Like
               the readvar  command, except the query is done for  each  of  a
               range  of  (nonzero)  association IDs. This range is determined
               from the association list cached by the  most  recent  associa-
               tions  command.

       opeers  An  old  form  of  the  peers   command  with  the reference ID
               replaced by the local interface address.

       passociations
               Displays association data concerning  in-spec  peers  from  the
               internally  cached  list of associations. This command performs
               identically to the associations  except that  it  displays  the
               internally stored data rather than making a new query.

       peers   Obtains  a  current list peers of the server, along with a sum-
               mary of each peer’s state.  Summary  information  includes  the
               address  of  the remote peer, the reference ID (0.0.0.0 if this
               is unknown), the stratum of the remote peer, the  type  of  the
               peer  (local,  unicast,  multicast or broadcast), when the last
               packet was received, the  polling  interval,  in  seconds,  the
               reachability  register,  in  octal,  and  the current estimated
               delay, offset and dispersion of the peer, all in  milliseconds.
               The  character  in  the  left margin indicates the fate of this
               peer in the clock selection process. Following  is  a  list  of
               these  characters,  the  pigeon  used in the rv  command, and a
               short explanation of the condition revealed.

       space reject
               The peer is discarded  as  unreachable,  synchronized  to  this
               server (synch loop) or outrageous synchronization distance.

       xfalsetick
               The  peer  is  discarded  by  the  intersection  algorithm as a
               falseticker.

       The peer is discarded as not among the first ten peers sorted
               by synchronization distance and so is probably a poor candidate
               for further consideration.

       -outlyer
               The  peer  is  discarded by the clustering algorithm as an out-
               lyer.

       +candidat
               The peer is a survivor and a candidate for the combining  algo-
               rithm.

       #selected
               The  peer  is  a  survivor,  but  not among the first six peers
               sorted  by  synchronization  distance.  If  the  assocation  is
               ephemeral, it may be demobilized to conserve resources.

       *sys.peer
               The  peer has been declared the system peer and lends its vari-
               ables to the system variables.

       opps.peer
               The peer has been declared the system peer and lends its  vari-
               ables  to  thesystem variables. However, the actual system syn-
               chronization is derived from a pulse-per-second  (PPS)  signal,
               either  indirectly  via  the  PPS  reference  clock  driver  or
               directly via kernel interface.

               The flash  variable is a valuable debugging  aid.  It  displays
               the  results  of  the original sanity checks defined in the NTP
               specification RFC-1305 and additional ones added in NTP Version
               4.  There  are  eleven tests called TEST1  through TEST11 . The
               tests are performed in a certain order designed to gain maximum
               diagnostic  information  while protecting against accidental or
               malicious errors. The flash  variable is first  initialized  to
               zero.  If after each set of tests one or more bits are set, the
               packet is discarded. Tests TEST4  and TEST5  check  the  access
               permissions  and  cryptographic message digest. If any bits are
               set after that, the packet  is  discarded.  Tests  TEST10   and
               TEST11  check the authentication state using Autokey public-key
               cryptography, as described in the Authentication Options  page.
               If  any  bits  are  set and the association has previously been
               marked reachable, the packet is discarded; otherwise, the orig-
               inate  and receive timestamps are saved, as required by the NTP
               protocol, and processing continues.

               Tests TEST1  through TEST3  check the  packet  timestamps  from
               which the offset and delay are calculated. If any bits are set,
               the packet is discarded; otherwise, the packet header variables
               are  saved.  Tests TEST6  through TEST8 check the health of the
               server. If any bits are set, the packet  is  discarded;  other-
               wise,  the  offset  and delay relative to the server are calcu-
               lated and saved. Test TEST9  checks the health of the  associa-
               tion itself. If any bits are set, the packet is discarded; oth-
               erwise, the saved variables are passed to the clock filter  and
               mitigation algorithms.

               The flash  bits for each test read in increasing order from the
               least significant bit are defined as follows.



       TEST1   Duplicate packet. The packet is at best a casual retransmission
               and at worst a malicious replay.

       TEST2   Bogus packet. The packet is not a reply to a message previously
               sent. This can happen when the  NTP  daemon  is  restarted  and
               before somebody else notices.

       TEST3   Unsynchronized.  One or more timestamp fields are invalid. This
               normally happens when the first packet from a peer is received.

       TEST4   Access is denied. See the Access Control Options page.

       TEST5   Cryptographic  authentication  fails.  See  the  Authentication
               Options page.

       TEST6   The server is unsynchronized. Wind up its clock first.

       TEST7   The server stratum is at the maximum than 15.  It  is  probably
               unsynchronized and its clock needs to be wound up.

       TEST8   Either the root delay or dispersion is greater than one second,
               which is highly unlikely unless the  peer  is  synchronized  to
               Mars.

       TEST9   Either the peer delay or dispersion is greater than one second,
               which is higly unlikely unless the peer is on Mars.

       TEST10  The autokey protocol has detected  an  authentication  failure.
               See the Authentication Options page.

       TEST11  The  autokey  protocol  has  not verified the server or peer is
               authentic and has valid public key credentials. See the Authen-
               tication Options page.

       support include the following:

       certificate
               filestamp  Shows  the NTP seconds when the certificate file was
               created.

       hostname
               host Shows the name of the host as returned by the  Unix  geth-
               ostname()  library function.

       flags   hex  Shows  the  current  flag  bits,  where the hex   bits are
               interpreted as follows:

       0x01    autokey enabled

       0x02    RSA public/private key files present

       0x04    PKI certificate file present

       0x08    Diffie-Hellman parameters file present

       0x10    NIST leapseconds table file present


       leapseconds
               filestamp Shows the NTP seconds when the NIST leapseconds table
               file was created.

       params  filestamp  Shows the NTP seconds when the Diffie-Hellman agree-
               ment parameter file was created.

       publickey
               filestamp Shows the NTP seconds when the RSA public/private key
               files were created.

       refresh timestamp  Shows  the NTP seconds when the public cryptographic
               values were refreshed and signed.

       tai     offset Shows the TAI-UTC offset in seconds  obtained  from  the
               NIST leapseconds table.


       support include the following:

       certificate
               filestamp  Shows  the NTP seconds when the certificate file was
               created.

       flags   hex Shows the current flag bits, where the hex  bits are inter-
               preted as in the system variable of the same name. The bits are
               set in the first autokey message received from the  server  and
               then  reset as the associated data are obtained from the server
               and stored.

       hcookie hex Shows the host cookie used in the key agreement  algorithm.

       initkey key Shows the initial key used by the key list generator in the
               autokey protocol.

       initsequence
               index Shows the initial index used by the key list generator in
               the autokey protocol.

       pcookie hex  Specifies  the peer cookie used in the key agreement algo-
               rithm.

       timestamp
               time Shows the NTP seconds when the last autokey key  list  was
               generated and signed.



       pstatus assocID Sends a read status request to the server for the given
               association.  The  names  and  values  of  the  peer  variables
               returned  will  be  printed. Note that the status word from the
               header is displayed preceding the variables, both in  hexideci-
               mal and in pidgeon English.

       readlist [
               assocID  ]

               rl  [  assocID   ] Requests that the values of the variables in
               the internal variable list be returned by the  server.  If  the
               association  ID is omitted or is 0 the variables are assumed to
               be system variables.  Otherwise they are treated as peer  vari-
               ables. If the internal variable list is empty a request is sent
               without data, which should induce the remote server to return a
               default display.

       readvar assocID variable_name  [ = value  ] [ ...]

               rv  assocID   [ variable_name  [ = value  ] [ Requests that the
               values of the specified variables be returned by the server  by
               sending  a  read  variables  request.  If the association ID is
               omitted or is given as zero the variables are system variables,
               otherwise  they are peer variables and the values returned will
               be those of the corresponding peer. Omitting the variable  list
               will send a request with no data which should induce the server
               to return a default display.

       writevar
               assocID variable_name  [ = value   [  ...]   Like  the  readvar
               request,  except the specified variables are written instead of
               read.

       writelist [
               assocID  ] Like the readlist request, except the internal  list
               variables are written instead of read.


BUGS

       The peers command is non-atomic and may occasionally result in spurious
       error messages about invalid associations occurring and terminating the
       command.  The  timeout time is a fixed constant, which means you wait a
       long time for timeouts since it assumes sort of a worst case. The  pro-
       gram  should improve the timeout estimate as it sends queries to a par-
       ticular host, but doesn’t.



SEE ALSO

       Primary source of documentation: /usr/share/doc/ntp-*/ntpq.html



AUTHOR

       David L. Mills <mills@udel.edu>



ntp 4.1.1b-r5                                                          ntpq(1)

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