[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:
> 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 : 22.214.171.124 (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
More information about the questions