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NTP Pool Project Reaches 500 Servers
Posted by
CowboyNeal
on Sat Jan 14, 2006 11:19 AM
from the about-time dept.
from the about-time dept.
flok writes "Finally after 3 years the NTP Pool project has reached 500 servers! The NTP pool project tries to be an accurate and free time-source to every internet-connected device. Everybody who's system has running an NTP daemon which can give an accurate time-indication can join the project. Not only is it handy to have accurate time on your workstation to be able to see when you need to leave the house to catch the train in time, it is also usefull to be able to accurately correlate events between your system and others in case one gets hacked."
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NTP Pool Reaches 1000 Servers, Needs More 230 comments
hgerstung writes "This weekend the NTP Pool Project reached the milestone of 1000 servers in the pool. That means that in less than two years the number of servers has doubled. This is happy news, but the 'time backbone' of the Internet, provided for free by volunteers operating NTP servers, requires still more servers in order to cope with the demand. Millions of users are synchronizing their PC's system clock from the pool and a number of popular Linux distributions are using the NTP pool servers as a time source in their default ntp configuration. If you have a static IP address and your PC is always connected to the Internet, please consider joining the pool. Bandwidth is not an issue and you will barely notice the extra load on your machine."
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oooo so exciting (Score:5, Funny)
Re:oooo so exciting (Score:5, Funny)
And what if you're posting in one?
Parent
Re:oooo so exciting (Score:3, Insightful)
Re:oooo so exciting (Score:2, Funny)
I've always wondered about that phrase -- who is this "Matters", and why would I want to stuff him?
Even more puzzling: with what?
Trains aren't that reliable (Score:4, Insightful)
And what makes sure the trains are on time?
Re:Trains aren't that reliable (Score:2)
But... (Score:2, Informative)
However, congrats. I will continue to use your NTP servers for computer related crap well into the future.
Confused (Score:4, Funny)
Re:Confused (Score:2, Interesting)
Re:Confused (Score:5, Informative)
Accurate time is important when you are sharing resources with other computers. One example is running a build on an NFS share. If the file timestamps are wrong, then make may do unnecessary compiles, or skip files. Other protocols, like rsync, use timestamps to try to figure out whether updates are needed.
Parent
Re:Confused (Score:3, Interesting)
You would be amazed at the number of folks who figure its allright to do that, I mean its there, why not use it attitude? So no, no admin in his right mind would set that up. Or if he did, he should be dismissed as not
Your machine is going to party like it's 1999 .... (Score:3, Insightful)
There are some nifty bits of nastiness that can be delivered when a machine is privy to having its clock changed from afar.
Re:Your machine is going to party like it's 1999 . (Score:3, Insightful)
A proper NTP implemetation for a computer gathers information from several clock sources. The NTP protocol also has provisions to determine whether a clock is accurate or not based on the responses from other clocks. IIRC, this is called a "false ticker" in the spec.
Re:Your machine is going to party like it's 1999 . (Score:5, Informative)
Nothing.
However, NTP clients uses multiple servers and uses some fairly advanced correlation algorithms to detect outlyers and bad servers. The client configuration is your responsibility. So configure it to use a set of servers that you believe you can trust.
There are some nifty bits of nastiness that can be delivered when a machine is privy to having its clock changed from afar.
Then use the secure protocols.
Parent
Re:Your machine is going to party like it's 1999 . (Score:3, Informative)
All machines in the NTP pool are monitored for quality and if they are bad enough, they won't be put into the pool.
Also, it is recommended that you have at least 3, maybe up to 5, NTP servers so that you can detect a bad NTP server. (If you have one time server, you won't know that anything is wrong. If you have two, you will know something is wrong, but you won't know which NTP server is bad. If you have three or more, you can p
Cool (Score:2, Funny)
Oh, sorry I read that as NNTP
PCs keep lousy time. (Score:2, Interesting)
the clocks simply could not keep accurate time. I've bought 5 buck watches at wal-mart that
kept better time than my PCs. In some cases, they lose (or gain) several (somtimes tens of)
seconds per day.
Is it those Dallas chips that can't keep time? or is it the clock frequency division that
most PCs use?
Re:PCs keep lousy time. (Score:4, Informative)
You will see your 5 buck watch will track the time as good as the Dallas chips.
Temperature affects the speed of clocks.
Parent
Re:PCs keep lousy time. (Score:5, Interesting)
Anyway, about 2pm my board operator at the tv station I was the CE at came running into my office and said the tape machine was going crazy, he though it was running fast and the on air picture wasn't viewable even after being time base corrected.
He'd put that tape in 3 of them without making it work.
As I walked through the control room I was just barely aware that the air conditioning and all the fans in the transmitter seemed to be working real well. I looked at the tape machine, whose main drive motor was a synchronous type whose speed is locked to the powerline frequency, and it did indeed appear to be running fast by a rather large margin. Looking at a motorized wall clock, I noted it was about 18 minutes faster than my trusty timex. So I timed the wall clock second hand against the timex and came up with a powerline frequency of around 71 hz. Voltage was also up a bit, to about 130 at the wall socket, so my transmitter was running very well indeed.
Calling the local electrickery people, I got a number for the WAPA control center up in Utah someplace and called them up. Argueing with the sexytary for a couple of minutes I finally got through to an operator on duty, introduced myself as the CE at a tv station down in New Mexico and then asked him if his clocks were fast. He first didn't get it, then checked his watch against the wall clock and muttered OMG. He said I'll get that fixed asap and I hung up since there wasn't a watts line account there & Ma Bell was very proud of her daytime business rates...
About 2 minutes later you could hear the fans and stuff gradually slowing down, and it finally settled at about 59hz until time had caught up with the wall clocks again.
I think some folks either got some overtime or got to go home a few minutes early that day, so there were what one could have called collateral damages, if even only to the economy west of the mississippi. The whole west side of the country is all synched up, presumably so is whats east of the river. Anyway, it was such an odd occurance that I still have to grin when I recall it nearly 30 years later. One of those things that couldn't ever happen, but did.
--
Cheers, gene
Parent
more useful for nfs, clustering (Score:2)
Re:more useful for nfs, clustering (Score:2)
Well, it does matter for Kerberos / MS Active Directory authentication.
In any shared software development environment, time needs to be accurate or your builds will fail in strange ways.
And I'd like to be able to correllate our syslog output, too...
Re:more useful for nfs, clustering (Score:3, Funny)
Yeah, I didn't think it mattered too much on non-critical systems either. Then I ran MythTV and missed the last couple minutes on my Futurama episodes. Never again.
Why we removed our servers from the pool... (Score:5, Interesting)
I finally shut it down after one particular call, the third that week, where the caller was rude and abusive when I suggested that he should be doing more investigation about the traffic before calling someone else to complain about it. Being a public service, it's just not something that scales well to have to field these calls. I hated to do it, but it was just too much of a distraction.
I'm not saying that you shouldn't add your servers to the pool... I just thought it was an amusing story.
Sean
Re:Why we removed our servers from the pool... (Score:3, Interesting)
Uh, your servers are supposed to only reply with *ONE* packet.
That said, I have also had a few people complain to me about my machine attacking them because they have configured their machine to use the NTP pool. Over the last 2 years, it has totalled around 3, so you must have had really bad luck.
Overall, I have been very happy with my involvement with the NTP
Re:Why we removed our servers from the pool... (Score:2)
Be that as it may, tcpdump of that particular remote address showed one
request coming in and 10 responses going back, spaced at 1 second
intervals. This may be because the remote was making a request that
resulted in the 10 responses. I'd doubt it was a but in ntpd, but that
may be as well.
Sean
Re:Why we removed our servers from the pool... (Score:4, Informative)
See the "iburst" keyword in ntp.conf. This results in a burst of ntp packets at startup.
Parent
New Way uses HW (Score:5, Informative)
It is great that NTP is so widely distributed. It is typical that at the moment the old technology is finally working, there is an altogether better solution.
Re:New Way uses HW (Score:3, Insightful)
Besides, what a GPS receiver gives you is a stratum 1 host. What are you going to do, get a receiver per machine? Of course not, you connect it to one box with a NTP server, and make the rest synchronize with it.
Perhaps the usefulness of public NTP servers is somewhat less now, but they're still good to have. I'm sure at many companies buying a GPS receiver could be co
Re:New Way uses HW (Score:2)
If time really matters, you'll have one per machine. I wouldn't say "of course not," as you did. They only cost about $75 (US) now.
Re:New Way uses HW (Score:3, Insightful)
Also, not everyone wants to setup an antenna on the roof and wire it into the computer room.
For typical computer network purposes (where relative time accuracy is more important than absolute accuracy), NTP is a very good solution. It will get all systems on your lan within milliseconds or better, and the whole network within tens of milliseconds. It will be better than a message-based (no
Re:New Way uses HW (Score:5, Insightful)
Of course, most machines locked in a rack in a hosting facility don't have even the slightest chance of seeing enough sky to lock onto GPS, so it's safe to say that NTP's death or obsolesence is premature to announce just yet. :-)
--
-Chuck
PS: O Slashdot wizards, why does Slashdot's posting filter claim ntpq output is lame?
It's a conspiracy, I tell you, to force me to write more text!
Bah, that doesn't work, the lameness filter doesn't like a line filled with "=" signs at all, even if I use an <ecode> tag.
Parent
Re:New Way uses HW (Score:4, Insightful)
Unless your data center is inside a shielded room / underground / in the center of your building.
It is great that NTP is so widely distributed. It is typical that at the moment the old technology is finally working, there is an altogether better solution.
Its not a better solution - its a better solution in some cases.
NTP has the massive advantage of working anywhere you have a network connection and not requiring expensive hardware (GPS hardware you can attach to a PC & match the reliability of NTP is not your yum-cha $75 GPS unit)
Parent
Re:New Way uses HW (Score:3, Informative)
Also, the 1pps output of a $75 GPS unit is considerably more accurate than NTP if your network is subject to *any* sort of variable delay, which of course packet-based networks are.
Not that NTP isn't useful, just don't
Recommended NTP clients (Score:2, Informative)
Re:Recommended NTP clients (Score:2)
I run a pool server: some interesting bits (Score:4, Informative)
There is modest protection against bad servers in the pool. The time from pool servers is monitored and if a server seems insane it's taken out of the rotation.
My pool server gets about 14 requests a second from about 100,000 different IP addresses a day. Sadly, a lot of those requests are junk; 100 IP addresses account for 1/3 of all the requests I get. Fortunately NTP is a very lightweight protocol, so you can mostly ignore the spammy clients.
Re:I run a pool server: some interesting bits (Score:2)
I didn't realize Microsoft did this, but I know when I started buying Apple, I sure noticed it, and thought it was a very nice touch. Small things like this can give a lot of polish to a product.
UIC's "unofficial" time server (Score:5, Funny)
The naming standard for desktop machines was to take the employee's first name and concatinate it with the first letter of their last name. So my desktop machine was named "johns.cc.uic.edu". Tim's machine was named "time.cc.uic.edu" because his last name began with "E". (cc meaning a "computer center" machine.)
Apparently many many university departments and users poked around and discovered what was obviously an official time server and configured their computers to synchronize to Tim's desktop machine. Tim, of course, had set his computer's clock by the office clock and never given it a second thought.
Obligatory Grammar/Spelling Nazi (Score:2, Offtopic)
Re:500 (Score:5, Funny)
... because they clearly need more publicity to reach something like 5,000 :)
Parent
Re:500 (Score:3, Insightful)
Really? (Score:2)
Re:500 (Score:2)
A time service is a sensitive, but important, service to use. Having many reliable time servers to choose among will lessen the security risk of hacked servers, or servers just out of sync for some reason. A public timer server will see alot of traffic, so not everyone has the bandwidth nor the hardware.
The OpenBSD Network Time Protocol daemon [openbsd.org] selects randomly among various time servers, and is very easy to setup. However, if there are few time servers available, there is
Re:500 (Score:4, Informative)
Last year, the pool was falling behind on servers. More clients were joining than servers, so the load on each server was growing. Since then, Ask Bjørn Hansen has created a bunch of automated scripts to handle all of the servers and the server growth has taken off. We still need more servers, and 500 is a nice round number to give as an excuse to say "Please join the NTP pool!".
Parent
Stratums (Score:5, Insightful)
It would also be nice if ISPs would set up their own pools (and advertise them) so clients wouldn't have to go off network, and then if end-users would would set up their own pool for their networks. Not every machine that needs accurate time has to be at stratum-2 or stratum-3, especially workstations. The NTP Pool website makes it look like it is a good idea if every machine on a network syncs to the NTP Pool, instead of setting up internal servers, which is how NTP is really designed to work.
Parent
Re:Stratums (Score:2, Informative)
- Traceroute off your network, e.g. to cnn.com
- For each hop in the route, run 'ntpdate -q '
9 times out of 10, you'll find an NTP server one or two hops away.
Auto-configure ntp via dhcp (Score:3, Interesting)
Agreed. Most do, but as you mention, don't advertise them. I am not sure how many people would actually know what to do with them if they were advertised though.
It would be quite slick if they advertised them via DHCP, and clients used that info to auto-configure their ntp client. All quite possible and very easy to do by the ISP. NTP servers can be advertised via dhcp.
http://gento [gentoo-wiki.com]
Re:I just use my watch (Score:2)
Re:I just use my watch (Score:2)
Re:Public NTP server? (Score:3, Informative)
in this context, public probably means that the server's listed by pool.ntp.org [ntp.org]. isc also maintains a list of stratum 1 and 2 servers [isc.org], some of which are publicly-accessible.