This is a discussion on Problem with Linux Machine's Request for Time from an XP Machine within the Linux Networking forums, part of the Linux Forums category; I started a thread titled "Setting Up NTP for Time Sync" that seems to be getting a few ...
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I started a thread titled "Setting Up NTP for Time Sync" that seems to be getting a
few too many branches for myself and others to cope with. I'm going to discontinue it, and continue here with what I think is the most important point to consider. See below (The Problem). For any newcomers wandering into this territory, I'm only interested in the problem presented here. I'll try to be brief and as accurate as I can. I've included in the mail list those people who have at one time or another participated in the other thread. Thanks to all those people on that list for their continuing interest. Basic Environment Two machines are on my local network: solarblast, an XP Pro machine with SP2 (svc pck 2), and astropc with Linux RH9. Both machines can attach to the internet with a modem. The Linux modem is only there to conduct tests regarding the problem I present here. I want to have redhat-linux-date request from solarblast (XP) the time it has. I believe this is time kept by NTP (see comment just above ==== below). The XP is set from the internet once a day. An Attempt To Get Time The command tool, redhat-linux-date, allows me to supply the IP address of solarblast (192.168.0.3) or a list of names, clock.redhat.com, clock1.redhat.com, etc to access NTP servers. The ultimate question is why can't I synch off of the XP Pro machine from linux? Here's what I have discovered by operating on astropc( Linux). From the Linux machine, I can fire up redhat-config-date. I can specify a location for the ntp server. One of them, which I added to the list, is 192.168.0.3, which is my XP machine. Another, provided by RH, is clock1.redhat.com. I deliberately set the clock off by 15 seconds in Linux. If I specify 192.xxxx, I do not get any correction. I then dial into my ISP from the Linux machine. I now use the tool again, but specify the clock1 entry. It resets the clock to the correct time. I again set the clock off by 10 seconds or so, and do the same with 192.xxxxx. Nothing. Repeated attempts with lesser time offsets produce no change in this test. Either XP isn't set up to deal with NTP or the request never makes it to XP. The Problem The question remains, why doesn't this work? Some insight to the answer is on the old thread, but I'm carrying this forth here. I do not expect to post there any longer. I will point people here though. At the moment of this post, it's quite possible that NTP doesn't really serve from the XP. I'm looking into this. ========================================== Here are some other items I know about this. (Undoubtedly I've omitted something, but here's what I can easily recall.) If necessary, I may post a separate thread which is meant to update the current status of the solution. It'll be called something like: STATUS: NTP and XP. Stay tunes. A. Pinging/Transfers I can ping either computer from its mate using their IP addresses. The net view (cmd line op) command shows both computers with their \\ names astropc2004 solarblast (this is XP) I can connect to the internet with either machine and download. I haven't quite figured out how to use Samba yet. If I boot up on the alternate OS, Win2k, on the Linux box, I can easily transfer data between W2k and XP and vice versa. B. XP cmd window command results I found via Help a command called net time. (*** Net timeSynchronizes the computer's clock with that of another computer or domain. Used without parameters, net time displays the time for another computer or domain. .... /querysntp Displays the name of the Network Time Protocol (NTP) server currently configured for the local computer or the one specified in ComputerName. ***) Executing net time /querysntp produces the result: The current sntp value is time.windows.com, 0x1 C. Firewalls (***Another bit of help from XP: Your personal or network firewall prevents clock synchronization. Most corporate and organizational firewalls will block time synchronization, as do some personal firewalls. Home users should read the firewall documentation for information about unblocking network time protocol (NTP). You should be able to synchronize your clock if you switch to Windows Firewall. I updated with SP2 recently, which has the new MS firewall. I had to remove McAfee in the process, so use MS at the moment. A few days ago, I just disabled it for about 10 minutes, but got the same results as above. No time set from XP. Otherwise, I really do not know how (yet) to just open a hole to NTP on XP when the firewall is up. ***) D. Registry There's a web page on the internet that suggests a fair number of changes should be made to the registry to get NTP running. I've ignored this for two reasons, but expect to do something about it today. First, when I found out about, it urges one to back up their registry. It took me awhile to figure this out, and be comfortable with the idea. I now can do it. Second, the print out of the page was so small, I didn't have a lot of faith I could really read it while trying to perform the steps. I finally figured out how to magnify the print out. See <http://support.microsoft.com/default.aspx?scid=kb;en-us;314054>. Possibly a related item is <http://support.microsoft.com/default.aspx?scid=kb;en-us;307897&sd=tech>. Haven't read it yet, but plan to real soon. Oh, yes, there's one other idosyncracy of the page. If I try to expand the print size, the right margin gets truncated. This makes it a bit dicey in trying to interpret long lines. Cute. E. Linux & Application I'm using RHL 9.0 and I'm aware of the fact it is out of date. It will have to do for the purposes of my NTP problem. RHL 9 is required for the application I'm using. The application is a video camera that collects images of fireballs (meteors). See <http://home.earthlink.net/~mtnv95959a/meteor_beginnings.html> for application details. For the sake of this problem, the sole focus of the effort is to understand how XP is going to provide the time to Linux, and not the other way around. Just bear with me on this. The IP addresses of the two machines I'm working with are 192.168.0.3 (XP) and 192.168.0.1 (Linux) F. Linux ntpdate In attempting to use ntpudate -d x, where I've used my local machines names and anything else that comes to mind, I get: "no servers can be used. exiting." What this means is unresolved. -- Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA) (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time) Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet Web Page: <home.earthlink.net/~mtnviews> |
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On Sun, 9 Jan 2005, W. Watson wrote:
> I started a thread titled "Setting Up NTP for Time Sync" that seems to be > getting a > few too many branches for myself and others to cope with. I'm going to > discontinue > it, and continue here with what I think is the most important point to > consider. See below (The Problem). > > For any newcomers wandering into this territory, I'm only interested in the > problem > presented here. I'll try to be brief and as accurate as I can. I've included > in the > mail list those people who have at one time or another participated in the > other > thread. Thanks to all those people on that list for their continuing > interest. > > Basic Environment > Two machines are on my local network: solarblast, an XP Pro machine with SP2 > (svc pck > 2), and astropc with Linux RH9. Both machines can attach to the internet with > a > modem. The Linux modem is only there to conduct tests regarding the problem I > present > here. I want to have redhat-linux-date request from solarblast (XP) the time > it has. > I believe this is time kept by NTP (see comment just above ==== below). The > XP is set from the internet once a day. a) AFAIK XP does not have the possibility of slewing the time, to compensate for rate errors in on board clock. Thus this procedure will mean that the clock time on the XP progressively gets out of sync, and then is brought back into sync once a day. Linux machines DO have the ability to slew, which means that they tend to maintain their accuracy throught the day, with only minor (millisecond) corrections when they b) NTP is not how the time is kept, it is how the time is transfered from one machine to the next. It is a protocol which trys to make machine B which is trying to synchronize to machine A as accurate as possible, which means compensating for time delays due to the programs themselves but more particularly due to the time it takes signals to propagate down the net between the two machines. There is a complex algorithm to do this. XP tends to abandon all of this which means that the time is only accurate to about +- 1 sec, instead of +- 1 msec. You will have to decide which you want. > > An Attempt To Get Time > The command tool, redhat-linux-date, allows me to supply the IP address of > solarblast > (192.168.0.3) or a list of names, clock.redhat.com, clock1.redhat.com, etc to > access > NTP servers. The ultimate question is why can't I synch off of the XP Pro > machine Because it is not running an ntp server. NTP servers do NOT come standard on Windows machines. You must get the software and install them and set them up. This is trivial to do on Linux. It is apparently much harder on XP. > > At the moment of this post, it's quite possible that NTP doesn't really serve > from the XP. I'm looking into this. Quite probably unless you set up NTP server software on the XP machine. > ... > /querysntp > Displays the name of the Network Time Protocol (NTP) server currently > configured for > the local computer or the one specified in ComputerName. > ***) > > Executing net time /querysntp produces the result: > The current sntp value is time.windows.com, 0x1 So the XP machine does have an npt client. But a client is not a server. > > C. Firewalls Probably irrelevant. Unless you have a firewall set up for your internal network. > D. Registry No idea. I do not do Windows. > E. Linux & Application > I'm using RHL 9.0 and I'm aware of the fact it is out of date. It will have > to do for ntp is 10 years old. This is not a problem. > the purposes of my NTP problem. RHL 9 is required for the application I'm > using. The > application is a video camera that collects images of fireballs (meteors). > See > <http://home.earthlink.net/~mtnv95959a/meteor_beginnings.html> for > application details. For the sake of this problem, the sole focus of the > effort is to > understand how XP is going to provide the time to Linux, and not the other > way > around. Just bear with me on this. > > The IP addresses of the two machines I'm working with are 192.168.0.3 (XP) > and 192.168.0.1 (Linux) > > F. Linux ntpdate > > In attempting to use ntpudate -d x, where I've used my local machines names > and anything else that comes to mind, I get: > > "no servers can be used. exiting." > > What this means is unresolved. What this means is that there are not servers ntpdate can use. However, I would advise you to use chrony, rather than xntp on your Redhat machine. chrony is precisely designed for cases where network access is sporadic. It also allows you to use your real time clock when your linux machine boots up, and corrects for its various problems. So again: Solutions a) get ntp server software for your XP machine. Install it. Make sure it is full ntp software, not simply SNTP which is a simplified protocol. b) Make your XP machine into a router for your linux machines. Then whenever your XP is connected to the net, so are the linux machines and they can get the time directly from ntp servers on the net. c) Keep the modem on the linux machines and have them call out once a day, and run chrony putting the net ntp servers online whenever your linux machines are connected. d) Buy a GPS receiver for your linux machines, install ntp and use it to keep the machines accurate to microseconds per day. > > PS, when you email other people, why do you give an invalid email address? You are emailing us, but refuse to let us email you. > |
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> In attempting to use ntpudate -d x, where I've used my local machines I assume that should be ntpdate. > names and anything else that comes to mind, I get: > > "no servers can be used. exiting." > > What this means is unresolved. What this means is that it couldn't find a server it could use. I just tried running ntpdate against a vanilla XP machine. I got this: $ ntpdate -q 192.168.1.111 Looking for host 192.168.1.111 and service 123 host found : xxxxxxxx server 192.168.1.111, stratum 16, offset 4.274011, delay 0.04193 9 Jan 14:49:03 ntpdate[31218]: no server suitable for synchronization found A look at the traffic (ethereal should be your friend) shows that the XP machine doesn't think its clock is synchronized with anything. This for what it's worth. I have no idea why XP thinks it is running an NTP server. It's connected to a network that has broadcast NTP, so it's not come configured to do anything sensible. Attempts to use ntpq to see what might be going on were rebuffed. Maybe the folks over on comp.protocols.time.ntp know. I *strongly* suggest searching archives and reading documentation before you post anything. |
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Bill Unruh wrote:
> On Sun, 9 Jan 2005, W. Watson wrote: > >> I started a thread titled "Setting Up NTP for Time Sync" that seems to >> be getting a .... snip >> I believe this is time kept by NTP (see comment just above ==== >> below). The XP is set from the internet once a day. > > > a) AFAIK XP does not have the possibility of slewing the time, to > compensate for rate errors in on board clock. Thus this procedure will .... > is full ntp software, not simply SNTP which is a simplified protocol. > b) Make your XP machine into a router for your linux machines. Then > whenever your XP is connected to the net, so are the linux machines and > they can get the time directly from ntp servers on the net. c) Keep the > modem on the linux machines and have them call out once a > day, and run chrony putting the net ntp servers online whenever your > linux machines are connected. > d) Buy a GPS receiver for your linux machines, install ntp and use it > to keep the machines accurate to microseconds per day. > >> >> > > PS, when you email other people, why do you give an invalid email > address? You are emailing us, but refuse to let us email you. > >> No problem, but I haven't actually refused anyone. Anyone who wanted it, I gave it to them. I'd prefer people that have posted here with help know my address. I still post anonymously. sierra_mtnview@earthlink.net-xyz. Just remove the -xyz. One never knows who's lurking out there. :-) I doubt they inspect msgs for addresses, but they certainly harvest from newsgroups. It's pretty clear after you and others have looked at the tcpdump that whatever NTP on XP is there it just isn't listening, so I'm heading for the registry edit approach to putting NP on my XP machine. I'll report back on this. Well, you've presented a new ripple above. GPS. I do happen to have a GPS unit. It's about six years old and made by Garmin. I inquired about its use on a GPS group, but prospects seemed a bit dim to use it. If you or others have suggestions, fire away. -- Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA) (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time) Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet Web Page: <home.earthlink.net/~mtnviews> |
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W. Watson wrote:
> > Well, you've presented a new ripple above. GPS. I do happen to have a > GPS unit. It's about six years old and made by Garmin. I inquired about > its use on a GPS group, but prospects seemed a bit dim to use it. If you > or others have suggestions, fire away. > Does it have a NMEA output? -- Tauno Voipio tauno voipio (at) iki fi |
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W. Watson wrote:
> > Well, you've presented a new ripple above. GPS. I do happen to have a > GPS unit. It's about six years old and made by Garmin. I inquired about > its use on a GPS group, but prospects seemed a bit dim to use it. If you > or others have suggestions, fire away. > Have a look at <http://www.digitalmapping.sk.ca/Networks/NTP/Default.asp>. It could help you to start with the GPS. IMHO, it's the way to go: GPS and NTP on the Linux machine = stratum 0 server. You could even sync the XP to it. -- Tauno Voipio tauno voipio (at) iki fi |
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Allen McIntosh wrote:
> >> In attempting to use ntpudate -d x, where I've used my local machines > > I assume that should be ntpdate. > .... > not come configured to do anything sensible. Attempts to use ntpq to > see what might be going on were rebuffed. Maybe the folks over on > comp.protocols.time.ntp know. I *strongly* suggest searching archives > and reading documentation before you post anything. Thank you for your input. I'll check against my system. I've been hearing favorable things about ethereal. I think my focus now is the (authorative time set) and XP modification of the registry document for NTP mentioned above. -- Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA) (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time) Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet Web Page: <home.earthlink.net/~mtnviews> |
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Tauno Voipio wrote:
> W. Watson wrote: > >> >> Well, you've presented a new ripple above. GPS. I do happen to have a >> GPS unit. It's about six years old and made by Garmin. I inquired >> about its use on a GPS group, but prospects seemed a bit dim to use >> it. If you or others have suggestions, fire away. >> > > Does it have a NMEA output? > Yes. -- Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA) (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time) Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet Web Page: <home.earthlink.net/~mtnviews> |
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Tauno Voipio wrote:
> W. Watson wrote: > >> >> Well, you've presented a new ripple above. GPS. I do happen to have a >> GPS unit. It's about six years old and made by Garmin. I inquired >> about its use on a GPS group, but prospects seemed a bit dim to use >> it. If you or others have suggestions, fire away. >> > > Have a look at > <http://www.digitalmapping.sk.ca/Networks/NTP/Default.asp>. > > It could help you to start with the GPS. IMHO, it's the way to > go: GPS and NTP on the Linux machine = stratum 0 server. > > You could even sync the XP to it. > I'll check it out. My GPS unit seldom gets used, so it's a candidate when I'm not roaming around the country side. I'm still going for the registry change to accomodate NTP today. I want to at least get on the record for go/no go on that. -- Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA) (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time) Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet Web Page: <home.earthlink.net/~mtnviews> |
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>>> GPS. I do happen to have a >>> GPS unit. What kind? >>>It's about six years old and made by Garmin. I inquired >>> about its use on a GPS group, but prospects seemed a bit dim to use >>> it. If you or others have suggestions, fire away. >>> >> >> Does it have a NMEA output? >> > Yes. PPS? |
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