More ntp fun: I now have multicast ntp time working and documented. With the listed ntp key clients can use
the multicasted network time from ntp.cs.uu.nl. The outgoing timestamps look
like this in tcpdump:
14:45:06.821419 IP (tos 0x0, ttl 30, id 6195, offset 0, flags [none], proto 17, length: 96) 131.211.84.189.ntp > 224.0.1.1.ntp: NTPv4, length 68
Broadcast, Leap indicator: (0), Stratum 2, poll 6s, precision -19
Root Delay: 0.000000, Root dispersion: 0.001724, Reference-ID: 127.127.22.0
Reference Timestamp: 3424077852.817587474 (2008/07/03 14:44:12)
Originator Timestamp: 0.000000000
Receive Timestamp: 0.000000000
Transmit Timestamp: 3424077906.819248263 (2008/07/03 14:45:06)
Originator - Receive Timestamp: 0.000000000
Originator - Transmit Timestamp: 3424077906.819248263 (2008/07/03 14:45:06)
I also see multicasted time from 192.36.143.151 (time2.stupi.se) but I can't
find a key for it.
2008-07-03 (#)
A new peak in ntpd traffic on ntp.cs.uu.nl : 1986 packets/second. From a very limited peek at the IP numbers it seems the 'friends' at turkish telecom were quite interested in the correct time.
2008-05-19 (#)
I found a really neat description of a project to build an accurate NTP stratum-0 server with the garmin gps 18 lvc.
2007-12-22 (#)
At work we now graph several temperatures in the serverroom (results are not public). We joked (or not..) last Friday that we could add a lot of sensors inside and outside the serverroom (that is where my thinking about 1-wire systems came in again) and have someone research this micro-climate and correlate the micro-climate with the ntp statistics. We did see the influence of the cold wind from the east on the pll stats of several ntp servers.
2007-09-25 (#)
About one and a half hour later, ntp.cs.uu.nl peaked at 1000.60 packets/second.
2007-09-25 (#)
I'm a timegeek, and part of that is making our timeserver at work perform great in the NTP Pool project. With the recently updated pool dns system, servers that have more upstream bandwidth get more clients. We have been ogling our ntp stats for ntp.cs.uu.nl a lot seeing how the client count is through the roof (the internal data structures of ntp can't count beyond 3500 clients without serious hacking) and traffic is rising seriously lately. Still waiting for the first time we get over 1000 packets/second ntp traffic. Our ntp server has no problem at all dealing with this.
2007-09-06 (#)
Timegeeks who can make the serious commitment towards being a long-time ntp pool member but don't have the hardware available to pick that last nanosecond of precision from the sky should peek at this announcement: Meinberg is donating some really great timekeeping equipment to the ntp pool project and it will be available to a pool member.
2007-05-15 (#)
I played with Asterisk scripting last evening. Started out with an empty extensions.conf and went from there to create a speaking clock. I was trying to copy the old Dutch ptt telecom 002 experience, with a Dutch voice I found at VoIP wiki nl: Asterisk en taal afhankelijke sound files. I run this ofcourse on a ntp-synchronized server, a talking clock has to be correct! I tried to make it run on intervals of 10 seconds, but that doesn't work completely yet.
2007-03-07 (#)
Sometimes you run into a very oooh, shiny! subject when looking for something else. I visited David Taylor's pages looking for his writeup of FreeBSD NTP server with an external GPS mainly to 'compare notes' with my own FreeBSD ntpd PPS setup (PPS slave) writeup. No surprises there, but one click led to the other, when I found out that David Taylor is also interested in receiving weather information and dove into that. He has a nice overview of his experiments in weather satellite receiving and decoding and I found out about EUMETCast data where you can receive weather satellite images via a satellite dish. Which uses a 'data' PID on a transponder, which is implemented as multicast data streams. Several personal interests for me and work-related stuff comes together in this. It's good to know this exists, but I won't be running out to buy a satellite weather map receiver now.
2007-01-02 (#)
I've been thinking about building a weather-station / ntp server with solar power for a while, and decided to start documenting the design, the ideas and the (lack of) progress. Named project sundial because it uses the sun to tell time, just in a somewhat convoluted way.
2006-04-26 (#)
Wrote a bit on how I configured FreeBSD as a PPS slave.
2006-04-14 (#)
Speaking of FreeBSD and ntp: yesterday at work I set up a Dell Poweredge 2550 as ntp server. FreeBSD 5.4, a kernel with PPS support (the PPS bits will arrive when I have time to make a cable). It now runs over the weekend to see how stable ntpd will get.
2006-04-14 (#)
Another problem with a public NTP server: Poul-Henning Kamp runs an NTP server on the Danish internet exchange DIX. He found out D-link routers all hammer on that NTP server (and lots of others) without any prior agreement. Read his Open Letter to D-Link about their NTP vandalism and Richard Clayton's write-up on how he researched the problem and found the source in the D-Link equipment. NTP was one of the last services that you could run cooperatively and assume your clients would play nice, now with 'home broadband routers' everywhere out in the world who like to keep the right time (and use sloppy-programmed client software to get that time), this trust in cooperative clients has been broken several times. Yes, this looks a lot like the former case with the University of Wisconsin - Madison and Netgear routers. At least, that case was solved with a good fix and an apology from Netgear.
2006-01-02 (#)
I watched the leap second on my rikaline gps and .. nothing happened. It just jumps from 2005-12-31 23:59:59 UTC to 2006-01-01 00:00:00 with nothing in between. Other sources did show a real leap second or an adjustment after the fact.
2005-05-19 (#)
Yes, Windows can be educated to accept the onboard clock in UTC. It's just not documented (duh). But Casper Dik has the answer: how to set solaris and windows to have the onboard rtc in UTC.
2003-03-10 (#)
I bundled the scripts I use to collect ntp stats in mrtg so other people can enjoy them too.