NTP is the network time protocol. It's used to keep all the computers in a network syncronized to the same time source. It uses stratums which are just trust levels to determine who has an authoritative time. The lower the number the better the trustworthiness. So a Stratum 1 clock is the best, and it would be syncronized to a Cesium clock, or some other accurate timesource. Some very large sites will sync to Stratum 1 clocks, but if you wish to do so you need to ask permission first. Most large networks sync to one, or multiple public Stratum 2 servers that are available.

Cheap, accurate clocks that sync to sattalites can be bought for $3000 (US) now. But I can't remember the company that makes them.

Windows 2000

If you want your Windows 2000 computer to automatically correct its clock (so you don't have to) then you'll be glad to know that it comes with built-in software to do so.

First of all, you will need to find an NTP server. Many ISPs provide one, so look at the tech support section of their web site. Often an ISPs Domain Name servers will also run an NTP service. If you can't find one then check the list of public NTP servers at <http://www.eecis.udel.edu/~mills/ntp/servers.html> for one close to your location.

Log in with administrative privileges and go to the command prompt. Run the Net command in this way:

net time /setsntp:ntp.server.com

where ntp.server.com is the address (it can be an IP address) of your NTP server. If you want to specify multiple servers then you can do so, if you separate them by spaces and enclose the entire list with double-quotes (").

To test your server, run w32tm -v -once -test and examine the output. This command attempts to synchronise with the NTP server(s), and the arguments you passed it tell it to print the output to the screen (verbose), to only synch once and to not attempt to actually set the system clock.

If all went well then you should see "48 bytes received" somewhere in the output. If not, try a different server. If you are behind a firewall you will have to make sure that the packets from the NTP server are able to reach you - NTP uses UDP, port 123.

Once you know your server works then go to the Services Manager (run services.msc). Scroll down to the Windows Time service and set it to Automatic. Start the service.

Your computer will now attempt to synch every 45 minutes, until it gets three good synchs, after which it will synch once every eight hours.

Never adjust your clock again! :)

Windows XP

Fire up the Group Policy editor (gpedit.msc) and hop to Local Computer Policy | Administrative Templates | System | Windows Time | Time Providers and set the options there. You will have to enable the NTP Client, set the server name to something appropriate and set the Type to NTP.

After you affect the changes you will see a status report in the System Event Log. To force a manual resync, use w32tm /resync.

carnun writes, in ntp you talk about setting up WinXP for ntp. AFAIK the Win implementation is actually of SNTP and is designed to provide accuracy between .5 and 2 secs. Who am I to argue?

Debian GNU/Linux

As root, run apt-get install ntpdate. Debconf will prompt you for an NTP server; enter one from the list above. Your clock will be synched immediately, as well as once during boot, or more often if you put /etc/init.d/ntpdate restart in a cron job. If you want to serve time data to your network, check out the ntp package.

Less interestingly, this is also a TLA for Nucleotide Tri-Phosphate. As in ATP, GTP, XTP (xanthine triphosphate) or 6-O-Methyl-weirdly-hypermodified-nucleotide triphoshate.

In some ways, this is similar to the use of 'sugar' to describe any CHO compound that can form a ring or conforms to certain other rules. Of course, as with any human defined set, there are exceptions. I just can't think of any at the moment...

NTP, the Network Time Protocol, is the brainchild of Dr. David L. Mills of the University of Delaware. It is both a software package and a protocol to synchronize the clocks of computers over a network, such as the Internet. In addition to downloading a time stamp from one or more servers, NTP compensates for connection latency, network faults, bad time servers, and the drift of the oscillation frequency of clock oscillators. Because it is capable of detecting the drift in a computer's clock, NTP can compensate for the drift even after being disconnected from a network, within a reasonable tolerance. Because of this, NTP does much more than assure that your clock is correct whenever it downloads time from a server: It makes sure your clock is always correct, even in the gaps between synchronizations. NTP is very good at what it does, and provides time synchronization on the order of a handful of milliseconds over a reasonable low-latency connection, and accuracy of around 50-100 milliseconds over poor network conditions.

The official NTP distribution, written by Mills and a considerable number of contributing programmers and maintainers, is written for Unix and Windows computers, and ports can be found for just about every operating system. The NTP team goes out of its way to maintain the distribution for a number of archaic Unix varities, including Ultrix, OSF1 (4.0), Tru64 Unix (5.x), and HP-UX, in addition to the more standard fare of Solaris, *BSD, and Linux. A number of dedicated timekeeping devices such as TrueTime GPS receivers have embedded NTP connectivity. GPS is the most common way for a stratum 1 NTP server to get its time.

In order to provide reliable and secure service, NTP supports completely authenticated and encrypted communications. This requires significant setup, but if you're working to provide an NTP server for your company or network, you may do well to investigate this.

The NTP research project has been heavily funded by DARPA, and is used by the U.S. Military for many, many things. NTP has recently been used by NASA, and the research group is of, as of this writing, attempting to deal with timekeeping issues involved in synchronizing time between different planetary bodies, in preparation for deep space missions involving time-critical devices. (In space travel, everything is time-critical.) The NTP research lab is one of the centers of research for the "Interplanetary Internet".

Information on NTP can be taken from the official website, at http://www.ntp.org/. Mills maintains further documentation that can be found linked there. The NTP web site is hosted at the electrical and computer engineering department at the University of Delaware, where a large testbed for the software distribution is maintained. The RFC that describes NTP is 1305, and the Simple NTP protocol, which is less feature-rich, is described in a chain of RFCs currently ending at 2030.

NTP is currently a draft standard for the Internet, and will remain so only because Mills refuses to provide an official ASCII version of the RFC, instead preferring to use postscript. Rumor has it that the RFC for the (current) NTP version 4 will consist of an ASCII document with nothing but links... "To read how the protocol works, see this postscript document. For network information, see here." etc. Mills can be a bit stubborn at times.

The NTP testing lab is located in Evans Hall at UDel. Official titled the "Internetworking Research Lab", the lab is unofficially known as the swamp, in reference to Walt Kelly's comic strip, Pogo. All of the machines in the lab are named after various pogo characters. If you ever download time from rackety.udel.edu (A stratum 1 server), that's where the name came from. Mills is a huge Pogo fan, and Pogo images, along with images from Alice in Wonderland litter the NTP documentation. His assertion that the Cheshire cat's hiding is like cryptography is somewhat dubious; it always seems more like security through obscurity to me.

References: NTP.org, Mills himself, and experience with the software. I am, as of this writing, the system administrator for the NTP research lab.

Net-speak abbreviation for need to pee. Be not fooled by its seeming rarity. Though you will not often need to pee during a conversation, when nature calls, you will be ready to make haste with this acronym. Much more descriptive than the generic BRB, this lets you know that your friend is important to you, and only the crushing pressures upon your bladder can tear you away. "Fear not my friend! I will return shortly." BRB simply does not hold that promise.

Contrast with the usual dishonesty of ROFL.

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