Tag Archives: gps

NTP Spoof Attacks

Apparently 2 out of 3 of our GPS clocks were being used in a spoof/DDOS attack.

The basic premise is that time requests are sent to the service with a spoofed IP for the response. Add in 100/1000/10000 clocks send results to a server/service that did not request them results in a denial of service attack.

Both clocks have been removed from the pool, scheduled for February 6th. Hickory.kulish.com has port 123 UDP closed at this time. The maintainer of Dickory.kulish.com has been notified.

Pi GPPS Clocks

Use Chris’ PPS kernel (until I have time or am compelled to compile my own).

Compile ntp 4.2.6p5 as follows (from aquarat):
But first: apt-get install libcap-dev

./configure --enable-ATOM --enable-NMEA --enable-linuxcaps; make; make install

Disable TTY on /dev/AMA0 in /boot/cmdline.txt
dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait

Set baud rate in /boot/config.txt
init_uart_baud=9600

and
Disable GPU sdram pause
# Disable GPU sdram mem pause
disable_pvt=1

Comment out getty in /etc/inittab:

#Spawn a getty on Raspberry Pi serial line
#T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100

Add pps-gpio to /etc/modules

Google Maps and your Garmin on Ubuntu and Windows

Or, “Where the hell are we?!” Part 2:

I recently bought a Nuvi 255W for some business travel coming up. I didn’t want to install Map Source since I don’t plan on buying any map packs any time soon. What I found was Garmin Communicator.

Windows:
Straight forward download and install.

Linux (Ubuntu):
apt-get install wine-gecko
Download Garmin Communicator
Download Firefox for Windows
Use wine to install Firefox and the Communicator plugin

Maintenance: gps.kulish.com

The gps.kulish.com FQDN will be re-directed to our backup stratum 2 server during a short maintenance window from 1700 – 2000 CDT US.

ntp pool clients should see no interruption in services. However, this means that kulish.com will be providing a stratum 2 time source while the gps is offline. **

Stratum 1 services are expected to resume at, or before, 2000 CST.

During maintenance we will be making final adjustments to the GPS system before going “live”.

** A second stratum 1 server will be coming online Q2 2008 to avoid the stratum bump in the future.

NTP: ntpq output explained

Host1:~# ntpq -p
remote refid st t when poll reach delay offset jitter
==========================================================
-navobs1.oar.net .USNO. 1 u 958 1024 377 89.425 -6.073 0.695
*navobs1.gatech. .GPS. 1 u 183 1024 375 82.102 1.639 0.281
-NAVOBS1.MIT.EDU .PSC. 1 u 895 1024 377 90.912 -0.207 0.368
+navobs1.wustl.e .GPS. 1 u 48 1024 377 76.890 1.093 0.525
-bigben.cac.wash .USNO. 1 u 924 1024 377 113.327 0.028 0.326
+tick.ucla.edu .GPS. 1 u 107 1024 377 102.470 2.032 0.482
-ntp.alaska.edu .GPS. 1 u 881 1024 377 168.741 5.180 5.157
-tock.mhpcc.hpc. .GPS. 1 u 933 1024 377 174.518 -1.094 0.054