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D-Link Settles Danish Time Dispute
igb writes "The Register reports that DLink has settled the time server dispute described a little over a month ago here on Slashdot. They're going to stop using an NTP server they're not really authorized to chime with, and they've reached an amicable settlement over the use by existing products. The details of the settlement are, not unsurprisingly, somewhat vague, but let's hope that the good guys aren't out of pocket any more."
Public or not, you have to follow the rules. It is pretty well known that only 'Stratum 2' NTP servers are to use 'Stratum 1' NTP servers. This is not just a 'because we want it that way' policy. There are many good reasons for this.
http://en.wikipedia.org/wiki/NTP_vandalism
"If you make people think they're thinking, they'll love you; But if you really make them think, they'll hate you." - DM
Yes, and yes. They are clueless, and they are cheap.
That is why pool.ntp.org was created - to provide a pool of NTP servers that these bozos can use without hammering anybody's server too badly.
www.eFax.com are spammers
These situations make no sense to me. The NTP system is very easy to use properly.
There's a great little website about how to use ntp.org servers properly.
For the quick-fix people, point your NTP capable system at pool.ntp.org.
If you live in north america, you can use the north-america.pool.ntp.org dns name instead, for only north american servers. The same applies to other continents and several country codes.
Basically, there's no excuse for hard-coding a time server in almost any situation, unless your client is completely incapable of DNS and has no access to external DNS servers.
- Michael T. Babcock (Yes, I blog)
Agreed. D-Link appears to occupy a point on the cost-quality curve that ultimately costs more in hair-pulling time than it saves in cash. Their products may be OK for lightweight use at home, but they can really give you fits in a more demanding environment.
Case in point: we recently put a bunch of DGS-1008D 8-port gigabit switches into service, and immediately started having problems with dropped Ethernet connections. Our laser printer was sucking down enough power at the onset of its fuser-warmup phase to trigger a nearby UPS momentarily. The resulting switchover transient lasted only a few milliseconds, but it was enough to reset the DGS-1008D. After a LOT of tail-chasing, it transpired that the (cheap-ass linear) wall-wart supplies that D-Link ships with the DGS-1008D lack sufficient filter capacitance to absorb even the slightest power glitch under high-load conditions (e.g., when there are several cables plugged into the switch.)
We took a few of their power supplies apart and found that the oldest ones -- which didn't have the problem -- used a 2000-uF filter capacitor at the rectifier output. At some point, they saved 10 cents by moving to a supply with only 1000 uF, rendering their product useless in many real-world office environments.
This isn't supposed to be a general "let's all bag on D-Link" thread, but hey, if the shoe fits...
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
- Stratum 1 are principle time servers for a region & directly query atomic clocks.
- Stratum 2 are general use for large regions or institutions - generally they should only be contacted by Stratum 3 servers - clients only as a last resort.
- Stratum 3 are the generic NTP servers of the internet - if you're an end client you should be talking to a Stratum 3 unless none are available/unrestricted for your use.
D-Link SOHO routers do 3 things wrong.- They don't follow the NTP protocol for requests to stop using the service.
- They ignore the restrictions place on the server usage - in Denmark, for use by ISP or Stratum (2/3) requests.
- They hit a Stratum 1 NTP server as an end client.
So no, if you run a public NTP server that you have dutifully entered restrictions on, you are expecting everyone who comes to you to obey the NTP protocol. That includes following the restrictions, listening to the go away requests, and following the basic rules of who to talk to.[Analogy type=bad]
In the US there are a number of parking spaces set asside for handicapped parking in almost every parking lot. Physically you can park there if you are not handicapped, but you're not supposed to (covers both ignoring restrictions and a client talking to a Stratum 1 server). If the manager of the parking lot tells you to get your car out of the spot - you should do that(refers to the kill request in the NTP protocol). In the real world if it get's this far, the cops come & give you a ticket. On the net you get open letters calling you an arogant prick who can't be bothered to figure out the basics of the protocols you are boasting about
[/Analogy]
For the record the Danish server was not the only Stratum 1 server they hit, they appear to have taken the Stratum 1 list (almost all of which restrict usage to Stratum 2 servers) and shoved it into the routers for general use - hardly the "Good internet citizen" they claim to be.
In my experience, when starting the 'chronyd' time daemon under Linux, it will poll very often, like 15 seconds intervals. Everytime it gets an answer, it will compare it to the system clock, log the deviation and adjust the system clock speed based on the trend. After some time, the system clock will run really accurate, so the logged deviations will be small. The polling interval will then be increased in steps up to a max. limit of 4 hours. If the computer is restarted, this scenario starts over again.
Compare this to a typical Windows XP computer which seems to poll a time server once a week or so. No doubt that the ntp server will feel some clients more abusive than others.
Disclaimers:
The intervals stated above may be wrong. I haven't tinkered with optimizing my time daemons since the old pay-per-minute ISDN days so my memory is a bit rusty.
Chronyd is just an example. I have no knowledge of whether it stresses the time servers more or less than other time daemons like 'xntpd'.
Poul-Henning Kamp got 200.000 DDK (Danish kroner) which is about 33.000 US$.
;-). This information is from the danish version of computerworld online at http://www.computerworld.dk/
;-)
The settlement states that Poul-Henning Kamp must not talk about the history of problems which the D-Link routers caused. But He tells danish press that any future problemes causes by D-link equiptment will be posted around the net
His homepage is http://people.freebsd.org/~phk/
For those in america: Denmark is not the capital of sweden