Re: [ntp:questions] ntpdate.c unsafe buffer write
David L. Mills wrote: Harlan, You make some good points. However, if folks want SNTP from here I think they would prefer it in its own distribution rather than bundle it with the huge NTP distribution. You can make a strong argument to host here I don't think you are ever going to get rid of ntpdate from the distribution (as supplied by packagers and vendors) until ntpd offers a mode which sets the time within about one second of being started. I'm not convinced that SNTP will displace ntpdate for this purpose. People don't want to delay boot sequences, but they also don't want to start applications until the time has been set. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpdate.c unsafe buffer write
David Woolley wrote: David L. Mills wrote: Harlan, You make some good points. However, if folks want SNTP from here I think they would prefer it in its own distribution rather than bundle it with the huge NTP distribution. You can make a strong argument to host here I don't think you are ever going to get rid of ntpdate from the distribution (as supplied by packagers and vendors) until ntpd offers a mode which sets the time within about one second of being started. I'm not convinced that SNTP will displace ntpdate for this purpose. People don't want to delay boot sequences, but they also don't want to start applications until the time has been set. How long does ntpd -g take to set the time? As I understand it, it's supposed to query the configured servers, make a best guess as to what time it is, set that, and then go to normal operation. That should put you within a second or so. If you need better, either wait for it, or keep your server alive 24x7x365. I think most data centers do run 24x7x365. If you're talking about a data center that lives under the boss's desk, consider buying a UPS and hope that the power doesn't fail for longer than the run time. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpdate.c unsafe buffer write
Richard B. Gilbert wrote: David Woolley wrote: David L. Mills wrote: Harlan, You make some good points. However, if folks want SNTP from here I think they would prefer it in its own distribution rather than bundle it with the huge NTP distribution. You can make a strong argument to host here I don't think you are ever going to get rid of ntpdate from the distribution (as supplied by packagers and vendors) until ntpd offers a mode which sets the time within about one second of being started. I'm not convinced that SNTP will displace ntpdate for this purpose. People don't want to delay boot sequences, but they also don't want to start applications until the time has been set. How long does ntpd -g take to set the time? As I understand it, it's supposed to query the configured servers, make a best guess as to what time it is, set that, and then go to normal operation. That should put you within a second or so. If you need better, either wait for it, or keep your server alive 24x7x365. I think most data centers do run 24x7x365. If you're talking about a data center that lives under the boss's desk, consider buying a UPS and hope that the power doesn't fail for longer than the run time. David is right. He means be done with it, including hard-setting the clock, within a second. The accuracy expected, based on ntpdate -b as the benchmark you are trying to replace, is within a small number of milliseconds of the specified servers. Sorry, ntpd -q doesn't meet the requirements. -Tom ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpdate.c unsafe buffer write
On 2008-02-09, Tom Smith [EMAIL PROTECTED] wrote: He means be done with it, including hard-setting the clock, within a second. The accuracy expected, based on ntpdate -b as the benchmark you are trying to replace, is within a small number of milliseconds of the specified servers. Sorry, ntpd -q doesn't meet the requirements. You need to be realistic about your requirements. In the case of systems which run time sensitive services, or are rarely rebooted, an ~11 second pause, which is _is_ about the amount of time it takes for 'ntpq -gq' to do a quick sanity check on your configured time servers and set the clock, is not unreasonable. In the case of systems which do not run time critical services there is no reason why ntpd can not be started with -g and be allowed to set the clock as the boot progresses. In most cases the clock will be set before, or very shortly after, the boot sequence is completed. The big issue in the ntpdate vs ntpd -gq debate is the fact that the former may be used over unprivileged ports while the latter can not. This gives ntpdate the advantage in situtations where a firewall is blocking port 123/UDP. That's what you should be complaining about, not some trivial 11 second delay. -- Steve Kostecke [EMAIL PROTECTED] NTP Public Services Project - http://support.ntp.org/ ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
[ntp:questions] GCC-4.2.3 Compiler Error in NTP-4.2.2p4
I tried to upgrade my ntp version running on a FreeBSD 6.3-STABLE system this morning and received the following error: if cc -DHAVE_CONFIG_H -I. -I. -I.. -I../include -I../include -I../libopts -I/usr/local/include -O2 -fno-strict-aliasing -pipe -Wall -Wcast-qual -Wmissing-prototypes -Wpointer-arith -Wshadow -Wstrict-prototypes -MT ntp_timer.o -MD -MP -MF .deps/ntp_timer.Tpo -c -o ntp_timer.o ntp_timer.c; then mv -f .deps/ntp_timer.Tpo .deps/ntp_timer.Po; else rm -f .deps/ntp_timer.Tpo; exit 1; fi ntp_timer.c: In function `reinit_timer': ntp_timer.c:104: warning: implicit declaration of function `timer_gettime' ntp_timer.c:105: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:105: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:106: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:108: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:109: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:111: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:111: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:112: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:113: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:115: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:116: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:117: warning: implicit declaration of function `timer_settime' ntp_timer.c: In function `init_timer': ntp_timer.c:170: warning: implicit declaration of function `timer_create' ntp_timer.c:182: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:182: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:183: error: invalid use of undefined type `struct itimerspec' ntp_timer.c:183: error: invalid use of undefined type `struct itimerspec' ntp_timer.c: At top level: ntp_timer.c:91: error: storage size of `itimer' isn't known *** Error code 1 Stop in /usr/ports/net/ntp. ! net/ntp (ntp-4.2.2p4) (new compiler error) The compiler is GCC-4.2.3_20080130 and the ntp version that I was attempting to upgrade to was ntp-4.2.2p4. This version was able to be upgraded using the default GCC compiler on another system. It would appear that GCC-4.2.3 does not like something in the 'ntp_timer.c' program. Is there something that I need to do for the upgrade to complete successfully? Tom -- Public Keys: PGP KeyID = 0x5F22FDC1 GnuPG KeyID = 0x620836CF ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpd not responding on localhost
Richard B. Gilbert [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Nick Bright wrote: ntpq pe remote refid st t when poll reach delay offset = 217.160.254.116 0.0.0.0 16 u- 12800.0000.000 75.144.70.350.0.0.0 16 u- 12800.0000.000 72.232.254.202 0.0.0.0 16 u- 12800.0000.000 208.75.88.4 0.0.0.0 16 u- 12800.0000.000 [...] Assuming that you waited at least 30 minutes before printing that ntpq banner, the servers you have configured are unreachable. Poll interval is at 128. It's been trying for some time, and already backing off. [...] AFAIK there is no good reason to block port 123. Your paranoia is slipping. The default state is closed, then if somebody comes asking you open a port... maybe. My firewall has a port 123 hole for the secondary server _only_ (which doesn't even use it, incidentally). The other hosts can get time from the firewall and its slave. I'm certainly not letting through NTP traffic for them. Groetjes, Maarten Wiltink ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
flyersix [EMAIL PROTECTED] writes: I have a network that I would like to cordinate the time in without exposing it to the internet for NTP servers. Could I just setup NTP on one of my internal servers and set the clients to go to it for time syncs? I know the time won't match the internet time but my thought is if I only need to change the time on the one server and then let the clients all go to it to update their time. Is this possible? Yes. Or if you have Linux, use chrony which is designed to allow you to set the time from your wristwatch, and use it as the ntpserver for the others using either ntp or chrony as clients. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
flyersix wrote: I have a network that I would like to cordinate the time in without exposing it to the internet for NTP servers. Could I just setup NTP on one of my internal servers and set the clients to go to it for time syncs? I know the time won't match the internet time but my thought is if I only need to change the time on the one server and then let the clients all go to it to update their time. Is this possible? Possible? Yes. Useful? Maybe! The problem with this is that your clock is not being disciplined. This means that, in addition to not necessarily having the correct time, it may not be ticking at exactly 1 second per second. Even worse, if the temperature is not controlled, the clock frequency and, therefore, the tick rate, can change from hour to hour. Now, imagine other machines trying to synchronize with this server. I think of it as one drunk driver trying to follow another. Nobody is going to crash into anything but the various machines trying to synchronize to the server will probably be all over the map. If you need or want tight synchronization, get an inexpensive GPS timing receiver. A Garmin GPS18LVC can be had for less than $100 US. You will need a soldering iron, a five volt power supply and a suitable connector (probably DB9 or DB25) to plug into a serial port. If you can site the antenna where it will have a good view of the sky, you should be able to synchronize your server to it with an accuracy that might be as good as 50 to 100 nanoseconds. Thus synchronized, the server should be stable as a table and should synnchronize your other machines quite closely, say within 50 or 100 microseconds. A lot will depend on the latencies within your LAN. Lightly loaded gigabit ethernet should do very well indeed if the network is small. Network switches can introduce unwanted random latencies. 100MB Ethernet also works quite well. I don't recall ever having used NTP over 10MB Ethernet but it's been years since I've seen one of those! ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpdate.c unsafe buffer write
In article [EMAIL PROTECTED], David Woolley [EMAIL PROTECTED] writes: David I don't think you are ever going to get rid of ntpdate from the David distribution (as supplied by packagers and vendors) until ntpd offers David a mode which sets the time within about one second of being started. The current sntp code can do this now. David I'm not convinced that SNTP will displace ntpdate for this purpose. Why not? David People don't want to delay boot sequences, but they also don't want David to start applications until the time has been set. Then I submit you are focusing a bit too deeply on the details and invite you to take a step back. I believe the current set of tools can be used in a variety of combinations that will handle the various cases to the best that we know how to do them. If you want to get the time set *now* and then start, regardless of how well the system can maintain that time, we can do that (sntp/ntpdate+ntpd). If you want to set the time ASAP and have stable system time before starting your apps, in the usual case you are talking about 11 seconds for this to happen (ntpd -g, with iburst, early in the boot sequence, using ntp-wait later in the boot sequence, just before starting time-critical services). Near as I can recall, any other cases have looser constraints so they're not particularly interesting for this conversation. -- Harlan Stenn [EMAIL PROTECTED] http://ntpforum.isc.org - be a member! ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
flyersix wrote: internet time but my thought is if I only need to change the time on the one server and then let the clients all go to it to update their time. ntpd isn't designed to cope with sudden step changes in time, as time doesn't behave like that. It will cope, eventually, but can take over an hour to recover from such an insult. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpdate.c unsafe buffer write
In article [EMAIL PROTECTED], David L. Mills [EMAIL PROTECTED] writes: David Harlan, You make some good points. However, if folks want SNTP from David here I think they would prefer it in its own distribution rather than David bundle it with the huge NTP distribution. That's not the feedback I have received, but I will note it would be possible to have an ntp+sntp distribution and a separate sntp distribution. It would take a couple of days' time to do this, and I have much hotter fires to put out first. Additionally, there will be significant changes in the code layout as the sntp code is overhauled, so I'd prefer to wait on this additional distribution tarball until that effort is completed. David You can make a strong David argument to host here if the claim that both NTP and SNTP are David strictly specification conformant. That's why I rewrote the SNTP David documentation to take out all mention that it could be used as a David server. OK. David The three of us that wrote rfc 2030 had just come down from a massive David clogging situation at UWisc and NIST and were frantic to get across David the need for polite client behavior. This has to do with DNS lookups, David poll intervals and behavior when no response is received. Even so, David there remains at least three violators of those principles right now David on two of our public servers. Therefore, if an SNTP product leaves David here, it really and surely should compley with the on-wire protocol David in the NTPv4 spec and these best practices. We're on the same page. David A aside, I should reveal my biases. At the moment, to configure the David current software on an Sun Ultra 5 takse 12 minutes, 6 minutes for David NTP and 6 minutes for SNTP. But, it takes only 8 minutes to compile David and link all programs, including both NTP and SNTP. It is not now David possible to build either separately. I'm not sure what you mean about building separately. We *used* to be able to build: - ntp + sntp: configure ; make - ntp only: configure --without-sntp ; make - sntp only: cd sntp ; configure ; make About a year and a half ago we got the SNTP code to the point where it would build on Unix (nobody has done the work for Windows, but apparently nobody is asking for it there either - http://bugs.ntp.org/500 has the details). Since we've been announcing that ntpdate will be deprecated because its functionality can be replaced by various combinations of ntpd and sntp, we made sntp a 'required' part of the NTP build. David As I have said privately before, the NTP daemon can be operated in David SNTP mode which does everything NTP does, but terminates just after David the clock has been set for the first time. Yes, it has a rather large David footprint, but it lasts only about 11 seconds. The downside is that David it requires a configuration file containing a list of servers. If David this were done on the command line, NTP in SNTP mode would be David indistinguishable from SNTP other than a command line option. You have provided a mechanism for doing this. It will be an acceptable choice for a good number of people. But there is a significant group of people for whom this particular mechanism will not work. They require any or all of the following: - a small footprint - set the time with the smallest possible delay While we might be able to achieve the smallest delay with ntpd, I don't currently see how we can do that while also offering full NTP support from a single binary and achieve the small footprint. David So, the ideal solution would seem to include a list of links on the David NTP home page to external sites and in addition internal links to the David NTP and SNTP distributions along with a statement that both are David strictly specification conformant. That might inspire other wannabees David to make and enforce similar claims. We already have internal and external links on the ntp.org site. And if somebody wants additional or different information there, contact information is also listed in what should be obvious places. -- Harlan Stenn [EMAIL PROTECTED] http://ntpforum.isc.org - be a member! ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpdate.c unsafe buffer write
Harlan Stenn wrote: Guys, This is all discussed pretty well at: http://support.ntp.org/bin/view/Dev/DeprecatingNtpdate So far everything I have seen in this thread has already been covered on that page. I just followed the above link. I see ONE feature missing! ntpdate -Du (I think it's -D) does NOT set the clock, it simply tells you what it would have done had it been permitted to do so. I suppose this feature is not essential but I've used it a time or two to find out how my time agreed, or disagreed, with some other server. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] GCC-4.2.3 Compiler Error in NTP-4.2.2p4
Tom, In article [EMAIL PROTECTED], Thomas Laus [EMAIL PROTECTED] writes: Thomas I tried to upgrade my ntp version running on a FreeBSD 6.3-STABLE Thomas system this morning and received the following error: Thomas The compiler is GCC-4.2.3_20080130 and the ntp version that I was Thomas attempting to upgrade to was ntp-4.2.2p4. This version was able to Thomas be upgraded using the default GCC compiler on another system. It Thomas would appear that GCC-4.2.3 does not like something in the Thomas 'ntp_timer.c' program. Is there something that I need to do for the Thomas upgrade to complete successfully? First, somebody gets to decide if this is really a bug in the NTP code or if it is a bug in GCC. If it's a bug in NTP (or perhaps even if it's not), somebody then gets to open a report at http://bugs.ntp.org. The odds are that if a patch to fix the problem is attached to that report it will be applied lots sooner. -- Harlan Stenn [EMAIL PROTECTED] http://ntpforum.isc.org - be a member! ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
Richard B. Gilbert [EMAIL PROTECTED] writes: flyersix wrote: I have a network that I would like to cordinate the time in without exposing it to the internet for NTP servers. Could I just setup NTP on one of my internal servers and set the clients to go to it for time syncs? I know the time won't match the internet time but my thought is if I only need to change the time on the one server and then let the clients all go to it to update their time. Is this possible? Possible? Yes. Useful? Maybe! The problem with this is that your clock is not being disciplined. This means that, in addition to not necessarily having the correct time, it may not be ticking at exactly 1 second per second. Even worse, if the temperature is not controlled, the clock frequency and, therefore, the tick rate, can change from hour to hour. So what? The other clocks will simply follow that one, whatever its time. If its clock drift rate is 300ppm there might be trouble, but in general that is not what happens. Now, imagine other machines trying to synchronize with this server. I think of it as one drunk driver trying to follow another. Nobody is going to crash into anything but the various machines trying to synchronize to the server will probably be all over the map. What does all over the map mean. they will be withing a few tens of microseconds of that server. If you need or want tight synchronization, get an inexpensive GPS timing receiver. A Garmin GPS18LVC can be had for less than $100 US. You will need a soldering iron, a five volt power supply and a suitable connector (probably DB9 or DB25) to plug into a serial port. Yes, that will give him an excellent time control But it does not seem he wants it. So why should he spend $100 and a day of his time installing it. If you can site the antenna where it will have a good view of the sky, you should be able to synchronize your server to it with an accuracy that might be as good as 50 to 100 nanoseconds. Thus synchronized, the Well, no, it will be within about 1usec, not nanosec. server should be stable as a table and should synnchronize your other machines quite closely, say within 50 or 100 microseconds. A lot will depend on the latencies within your LAN. Lightly loaded gigabit ethernet should do very well indeed if the network is small. Network switches can introduce unwanted random latencies. 100MB Ethernet also works quite well. I don't recall ever having used NTP over 10MB Ethernet but it's been years since I've seen one of those! It works fine. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] GCC-4.2.3 Compiler Error in NTP-4.2.2p4
First, somebody gets to decide if this is really a bug in the NTP code or if it is a bug in GCC. It could also be a glitch in the included header files. -- These are my opinions, not necessarily my employer's. I hate spam. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
What does all over the map mean. they will be withing a few tens of microseconds of that server. I'd expect a few to tens of ms rather than microseconds. If you manually set the time on the server, I'd expect it to take a while for the clients to catch up. This question comes up often enough that a wiki page seems like a good idea. -- These are my opinions, not necessarily my employer's. I hate spam. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
Unruh wrote: Richard B. Gilbert [EMAIL PROTECTED] writes: flyersix wrote: I have a network that I would like to cordinate the time in without exposing it to the internet for NTP servers. snip The problem with this is that your clock is not being disciplined. This means that, in addition to not necessarily having the correct time, it may not be ticking at exactly 1 second per second. Even worse, if the temperature is not controlled, the clock frequency and, therefore, the tick rate, can change from hour to hour. So what? The other clocks will simply follow that one, whatever its time. If its clock drift rate is 300ppm there might be trouble, but in general that is not what happens. Now, imagine other machines trying to synchronize with this server. I think of it as one drunk driver trying to follow another. Nobody is going to crash into anything but the various machines trying to synchronize to the server will probably be all over the map. What does all over the map mean. they will be withing a few tens of microseconds of that server. I mean that a system with a GPS based hardware reference clock synchronizes a mob of other machines more closely than a system using a bunch of internet servers can. The later case is more of a moving target. Those internet servers MAY know the correct time to within a few microseconds but, by the time the internet is done with the query and response packets, the time is a Scientific Wild Ass Guess with an uncertainty of many milliseconds. As ntpd changes its opinion as to who has the best time, and switches from server to server the time tends to bounce around a bit. As the internet changes its behavior from night-time not very busy to day-time traffic jam the quality of the time deteriorates. That rock solid GPS reference makes a big difference. ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
David J Taylor wrote: [] Your best bet is to get a local reference clock like a low-cost GPS receiver (about $50-$200 US). I described a simple system here: http://narvik/blueyonder/ntp/FreeBSD-GPS-PPS.htm Cheers, David Oops, that's: http://www.david-taylor.myby.co.uk/ntp/FreeBSD-GPS-PPS.htm David ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpdate.c unsafe buffer write
In article [EMAIL PROTECTED], David Woolley [EMAIL PROTECTED] writes: David Harlan Stenn wrote: In article [EMAIL PROTECTED], David Woolley [EMAIL PROTECTED] writes: David I'm not convinced that SNTP will displace ntpdate for this purpose. Why not? David Because ntpdate is fixed in the popular culture and, for the ordinary David user, SNTP doesn't offer any obvious advantages. Well, The Plan is to remove ntpdate. So unless somebody writes a contributed script, the fact that ntpdate (with its known bugs) is going away and a documented set of functional equivalents will be available will probably be all the convincing that is needed. If you want to get the time set *now* and then start, regardless of how well the system can maintain that time, we can do that (sntp/ntpdate+ntpd). David Not in Dave Mills future of ntpd, as you don't get ntpdate or SNTP. That would be true if Dave controlled the contents of the distribution. There is a set of required functionality out there that will be met by the distribution I control. There may be distributions I roll that have subset functionality, and Dave may choose to offer other distributions. I see no benefit and many problems in forcing this issue too soon, so at the moment it is a topic for discussion and the situation seems to be on track right now. This is, by no means, the most important thing we're all working on right now. Getting the sntp code up to spec is far more important, IMO. If you want to set the time ASAP and have stable system time before starting your apps, in the usual case you are talking about 11 seconds for this to happen (ntpd -g, with iburst, early in the boot sequence, using ntp-wait later in the boot sequence, just before starting time-critical services). David I suspect that only sets the time to the nearest 128ms, unless it David does something that ntpd doesn't normally do. I suspect you are mistaken, and what I describe is correct. In the case I describe, at the end of that O(11 second) period the clock is Real Close (ie, the offset is low enough), the frequency drift is known and compensated for, and ntpd is in state 4. -- Harlan Stenn [EMAIL PROTECTED] http://ntpforum.isc.org - be a member! ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] UML/architecture picture of NTP?
[EMAIL PROTECTED] wrote: I;ve downloaded the Development version 4.2.5p111 off NTP from http://www.ntp.org/downloads.html I want to make modifications to the included sources of the ntpd (NTP devel). First I need to know how it works, and how the different parts communicate. I need something like UML, or a architecture picture where I can see what is what etc. I couln't find this anywhere at ntp.org or google :s - UML diagrams - Overview of the protocol archtecture in a image in layers (for example like in the OSI model) All part defined in a image etc (I couln;t find this at NTP.org) There are plenty of use cases. I think that most of it should be done by the NTP Forum since there would be too much work to be done on a volunteer basis. Danny ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] NTP no internet connection
On 2008-02-09, flyersix [EMAIL PROTECTED] wrote: I have a network that I would like to cordinate the time in without exposing it to the internet for NTP servers. What level of time stability are you looking for? Could I just setup NTP on one of my internal servers and set the clients to go to it for time syncs? I know the time won't match the internet time ntpd does not synchronize to internet time. ntpd synchronizes computer clocks to a common timebase over networks; the ubiquitous, and cheapest, timebase is UTC. ntpd accomplishes this synchronization by steering, or disciplining, the system clock to bring it as close as possible to the best estimate of the common timebase. but my thought is if I only need to change the time on the one server and then let the clients all go to it to update their time. You can use ntpd for this purpose. Here's what you do: 1) Choose the system with the most stable clock to be the master clock for your time island 2) Configure your master and the clients as follows: -8X- # Server ntp.conf: # The ntpd user must be able to write to this drift file driftfile /path/to/ntp.drift # maxpoll 2 allows this ntpd to be ready to serve clients within # 60 seconds of start-up. server 127.127.1.0 maxpoll 2 -8X- # Client ntp.conf: driftfile /path/to/ntp.drift server your.master.ntpd iburst -8X- 3) Set the master clock by your wrist-watch and _then_ start ntpd, with '-g', on the master and the clients Once the master has drifted far enough from wrist watch time use the following steps to correct it: 1) Stop ntpd on the master 2) Reset the system clock (not the RTC) from your wrist watch 3) Start ntpd on the master You can improve the stability of the master clock by temporarily providing that ntpd a real timebase (either with a radio clock or via a network) and allowing ntpd to run long enough to calculate the frequency correct needed to keep your clock stable. Ideally the ambient conditions and system load for the server will be the same as your production environment. -- Steve Kostecke [EMAIL PROTECTED] NTP Public Services Project - http://support.ntp.org/ ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
