[ntp:questions] Re: abuse or bug ?

Richard B. Gilbert rgilbert88 at comcast.net
Thu Jan 27 12:55:18 UTC 2005


Henk P. Penning wrote:

>Hi,
>
>  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   : 129.105.100.183 (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
>    restrict 127.0.0.1
>
>  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  \_/
>
>  
>
This behavior has been noted in some Netgear routers and, perhaps, 
others as well.  In the case of the Netgear routers, an embedded SNTP 
client used a hard coded IP address, at the University of Wisconsin I 
believe!  The implementation was not standards compliant.

AFAIK this has not been a problem with the reference implementation of 
NTP 4.2.0.



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