[ntp:questions] abuse or bug ?

Henk P. Penning henkp at cs.uu.nl
Thu Jan 27 08:25:34 UTC 2005


  it has been noted that some clients poll time servers at
  a rate of 1 packet per second, for an unlimited period.

  Is this a bug in the standard ntpd software or
  abuse by bad software or badly configured clients ?

  The example below make me think it is a bug.

  client   : (in cs.northwestern.edu)
  hardware : Sun, SunBlade 150
  operating system :
    Linux gandalf 2.4.26-sparc-r2 #14 Wed Sep 22 15:27:12 CDT 2004 sparc64
    sun4u TI UltraSparc IIe (Hummingbird) GNU/Linux
  ntp      : ntp  4.2.0-r2
  config :
    server pool.ntp.org
    driftfile       /var/lib/ntp/ntp.drift
    restrict default notrust nomodify

  It has sent 438851 packets in the last 129.3 hours to 'ntp.cs.uu.nl'.
  The client says the server is unreachable.

  There may well be a problem with the client's ntpd config
  or the clients network setup ; the interesting thing is that
  standard ntpd software with a 'normal config', running on
  of-the-shelf hardware, can show the undesired behaviour.

  The contact for the client is Stefan Birrer (thanks for all
  the info) [s-birrer (at) northwestern edu].

  Henk Penning

----------------------------------------------------------------   _
Henk P. Penning, Computer Systems Group       R Uithof CGN-A232  _/ \_
Dept of Computer Science, Utrecht University  T +31 30 253 4106 / \_/ \
Padualaan 14, 3584CH Utrecht, the Netherlands F +31 30 251 3791 \_/ \_/
http://www.cs.uu.nl/staff/henkp.html          M penning at cs.uu.nl  \_/

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