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D-Link Settles Danish Time Dispute
Posted by
Zonk
on Thu May 11, 2006 02:40 PM
from the cash-out-your-chips-now dept.
from the cash-out-your-chips-now dept.
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."
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Technology: D-Link Firmware Abuses Open NTP Servers 567 comments
DES writes "FreeBSD developer and NTP buff Poul-Henning Kamp runs a stratum-1 NTP server specifically for the benefit of networks directly connected to the Danish Internet Exchange (DIX). Some time last fall, however, D-Link started including his server in a hardcoded list in their router firmware. Poul-Henning now estimates that between 75% and 90% of NTP traffic at his server originates from D-Link gear. After five months of fruitless negotiation with a D-Link lawyer (who alternately tried to threaten and bribe him), he has written an open letter to D-Link, hoping the resulting publicity will force D-Link to acknowledge the issue. There are obvious parallels to a previous story, though Netgear behaved far more responsibly at the time than D-Link seem to be."
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They should've known better... (Score:5, Funny)
Netgear did the same thing a few years ago (Score:5, Insightful)
It's strange these companies can't afford to set up a few of their own NTP servers instead of overloading servers that don't have the bandwidth. It it's because they are clueless or they are cheap?
Re:Netgear did the same thing a few years ago (Score:3, Informative)
I currently use the Argonne national lab NTP server most of the time which is probobly government paid though it could be provided by the University of Chicago (though since my connection is on-campus, it makes the most sense).
Re:Netgear did the same thing a few years ago (Score:5, Informative)
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.
Parent
Re:Netgear did the same thing a few years ago (Score:5, Informative)
There's a great little website about how to use ntp.org servers [ntp.org] 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 [ntp.org] 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.
Parent
Re:Netgear did the same thing a few years ago (Score:5, Interesting)
Parent
Re:Netgear did the same thing a few years ago (Score:5, Informative)
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'.
Parent
Re:Netgear did the same thing a few years ago (Score:4, Informative)
Yes, but worse and out of order
Check out NTP.org [ntp.org]. Specifically check the Rules of Engagement [isc.org], The Stratum 1 list [isc.org], and RFC 1305 [faqs.org].
Now looking at everything we have a protocol that involves 2 components, an implimentation component and a social component. The actual implimentation of the protocol is laid first as "Format your request in this fasion and we will return the responce looking like this...". However, it also has things for implimenting request timing fallback and kill requests. The social implimentation of the protocol is layed out in the RoE and the Server Lists - note the regional restrictions and the authorization requests in the server lists.
From the original article which evidently doesn't have any information on the open letter anymore - D-Link took the Stratum 1 list and shoved it into some of their router NTP lookup tables. That blows off the entire social aspect of the protocol - both the permissions and the structure.
Next they implimented only the request portion of the protocol, they ignore the backoff & get lost request structures - essentially forgoing the entire error correction portion incorperated into the RFC. So up to the point of manufacture they have 3 strikes against them,
- Failure to obey the Stratum structure of the NTP system
- Failure to follow the permisions structure of the NTP system
- Failure to properly impliment the NTP connection protocol
Now there was no known issue with this until the Danish exchange turned to the Stratum 1 owner and said "You are eating a hell of a lot of bandwidth here & we can't keep giving it to you for free." At which point the problem was tracked back to a series of D-Link SOHO routers. I don't recall the exact process he used , but he started sending kill requests to anything from a D-Link router. When they ignored it & kept making requests he talked to D-LinkFrom memory the conversation then went like this:
Dane: You're routers are hammering my server & they need to stop, you don't have permission & you're violating the rules.
D-Link: How cute, have a nickle & go get yourself some candy.
Dane: WTF? The exchange is going to charge me $8K to cover your protocol violations.
D-Link: It's not our fault & if it is talk to our Lawyer.
Lawyer: I won't talk to you unless you come to CA & argue your case.
At which point it devolved to an open letter & public shaming - which by the way seems to have worked.
[note] IIRC someone calculated the estimated bandwidth from the D-Link routers using Stratum 1 NTP servers to be enough to continously flood a T1. So this isn't just an occasional knock on the door, it's pretty heavy usage for what amounts to a request packet and a responce packet from each router.
Parent
They already lost at least $120 in sales (Score:5, Interesting)
And likely more. I've been telling my friends not to buy them, and I know of at least one buying decision that was made specifically for that reason that cost them $120 worth of sales of USB wireless adapters.
Re:They already lost at least $120 in sales (Score:5, Interesting)
I had even more fun letting the D-Link fuckheads know why they were on my blacklist. For two main reasons, the NTP theft of services from all the stratum 1's, and the mac ethernet framing problems. They were told quite clearly the non-response from their engineering team on these two show-stopper problems had left them permanently blacklisted. Its called schadenfreud, and it feels good.
the AC
Parent
Not Vague At All (Score:5, Insightful)
Part of the settlement involves him putting on his website "D-Link is dedicated to remaining a good corporate and network citizen."
Otherwise, considering his previous level of frustration, there's no chance he would shill for them like that.
not unsurprisingly (Score:5, Funny)
What I would have done (Score:5, Funny)
Re:What I would have done (Score:4, Funny)
Parent
Re:What I would have done (Score:3, Informative)
NTP Pool for Vendors (Score:3, Informative)
This should have been solved with a check. (Score:4, Insightful)
In the scheme of things, and from a marketing perspective, anything else is stupid and a waste of good will.
Poul-Henning Kamp got payed! (Score:4, Informative)
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/ [freebsd.org]
For those in america: Denmark is not the capital of sweden
Re:Public? Server (Score:4, Informative)
No.
Parent
Public yes, but with permission (Score:3, Informative)
The reason for this is to avoid problems like this, where the NTP server is overloaded or the NTP client is mis-configured and overloads the server or network.
Re:Public? Server (Score:5, Informative)
http://en.wikipedia.org/wiki/NTP_vandalism [wikipedia.org]
Parent
Re:Public? Server (Score:4, Informative)
- 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.
Parent
Re:Public? Server (Score:5, Insightful)
Also, his server is a Stratum 1, and, while not explicitly written, the D-Link devices should getting the time via a Stratum 2 server. At least, that's how it's commonly done.
Does that help explain things better?
Parent
Re:Public? Server (Score:4, Insightful)
Please, stop with stupid analogies. They are never helpful. You can leave your door open all the time, that doesn't give anyone the right to go in! In Vermont, thats criminal trespass, and the fine is much larger than the other forms of trespass defined in the act.
Parent
Re:Their reputation preceeds them (Score:5, Informative)
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...
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