Provided by: ntp_4.2.6.p3+dfsg-1ubuntu3_amd64 bug


       ntpdc - special NTP query program


       ntpdc [-ilnps] [-c command] [host] [...]


       ntpdc  is  used to query the ntpd 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 ntpdc
       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 ntpdc.

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

       ntpdc 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. ntpdc makes no attempt to retransmit requests, and will time
       requests out if the remote host is not heard from within a suitable timeout time.

       The  operation  of  ntpdc are specific to the particular implementation of the ntpd daemon
       and can be expected to work only with this and maybe some previous versions of the daemon.
       Requests  from  a  remote ntpdc 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.

       Note  that  in  contexts  where a host name is expected, a -4 qualifier preceding the host
       name forces DNS resolution to  the  IPv4  namespace,  while  a  -6  qualifier  forces  DNS
       resolution to the IPv6 namespace.


       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, ntpdc  will  attempt
       to read interactive format commands from the standard input.

       -4     Force  DNS  resolution  of  following  host  names  on the command line to the IPv4

       -6     Force DNS resolution of following host names  on  the  command  line  to  the  IPv6

       -c command
              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 ntpdc to operate in interactive mode. Prompts will be written to the standard
              output and commands read from the standard input.

       -l     Obtain a list of peers which are known to the server(s). This switch is  equivalent
              to -c listpeers.

       -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 summary of their  state.
              This is equivalent to -c peers.

       -s     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  -c


       /usr/share/doc/ntp-doc/html/ntpdc.html for the full documentation.