r8 - 2012-07-24 - 05:51:57 - DavidTaylorYou are here: NTP >  Support Web > InexpensiveOemGps
NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to use in a distributed denial-of-service (DDoS) attack. Please also take this opportunity to defeat denial-of-service attacks by implementing ingress and Egress filtering through BCP38.

A new set of mode 6 vulnerabilities has been discovered and, while these vulnerabilities can be reduced by making sure you have restrict default noquery in your ntp.conf file, the best and most complete way to avoid these vulnerabilities is to install and deploy ntp-4.2.8 which was released on 18 December 2014.

Please see the NTP Security Notice for vulnerability and mitigation details.

Are you using Autokey in production? If so, please contact Harlan - he's got some questions for you.

Inexpensive OEM GPS Receivers

With PPS

Garmin GPS-18LVC

Sure Electronics GPS Evaluation board

Without PPS

Globalsat BR-355, BU-353 and other modules using the SiRF chip sets.

These don't work very well. They have two problems.

  1. First is that they have a lot of jitter/wander. (The jitter is too low frequency to easily filter out.)
  2. Second is that they have a strange off-by-a-second bug if there is a leap second pending. This graph shows both quirks.
Topic attachments
I Attachment Action Size Date Who Comment
gifgif leap-gps2.gif manage 15.2 K 2008-11-21 - 05:19 HalMurray Plot of Leap Second glitch in SiRF chip sets
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