[ntp:questions] [Pool] 4000 packets a second?

Dave Hart hart at ntp.org
Wed Sep 1 01:37:05 UTC 2010

On Wed, Sep 1, 2010 at 00:42 UTC, David L. Mills <mills at udel.edu> wrote:
> Did you intend the discard minimum 0? That effectively disables the rate
> control defense mechanism. you should leave it out.

That has not been my experience on the pool server I'm involved with:

hart at pool1> fgrep discard /etc/ntp.conf
# discard minimum 0 (power of 2 like poll interval) is needed
discard minimum 0 average 3
hart at psp-fb1> ntpq -c sysstats
uptime:                 1059862
sysstats reset:         1059862
packets received:       263004216
current version:        144454930
older version:          99867648
bad length or format:   18635251
authentication failed:  316799
declined:               3179
restricted:             14857
rate limited:           56970859
KoD responses:          1405175
processed for time:     76220
hart at pool1> ntpdc -c sysstats
time since restart:     1059868
time since reset:       1059868
packets received:       263005578
packets processed:      76220
current version:        144455895
previous version:       99867947
declined:               3179
access denied:          14857
bad length or format:   18635348
bad authentication:     316800
rate exceeded:          56971000
hart at pool1>

A bit over 20% of incoming traffic has exceeded rate limits with
"discard minimum 0" used (1s minimum).

Dave Hart

More information about the questions mailing list