Setting up Windows XP as an NTP Server

  |   By

A network time server or NTP server (Network Time Protocol), is a central computer or server on a network that controls the time and synchronises all machines on that network to it.

Windows XP can be set up to operate as an NTP server to synchronise the rest of the computers and devices on a network. Setting up a Windows XP machine to act as a NTP server involves editing the registry, however, editing an operating system registry can lead to potential problems and should only be conducted by somebody with experience of registry editing.

To configure Windows XP as an NTP server the first thing to do is to open the registry editor in Windows. This is done by clicking the Start button and selecting “Run” from the menu. Enter “regedit” in the run menu and press return. This should open the Windows registry editor.

Select the: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer\ folder in the left hand pane. This folder holds the values for the NTP server.

Right-click the “Enabled” key in the right window pane and select “Properties”. This should open a dialog box where you can alter the value of the registry key. Enter “1” in the window, setting the value to “True” which turns the XP computer into a time server.

Close the registry and open the DOS command prompt by clicking the Windows Start button, selecting “Run”. Then type “cmd” in the text box and press return.

Type “Net stop w32time” into the command prompt and press “Enter.” Now type “net start w32time” this will restart the time server for Windows XP.

However, the XP machine, which is now set as a NTP server, will merely distribute the time it currently holds. If this time is inaccurate then it will inaccurate time that is distributed amongst the network.

To ensure an accurate and secure source of time is used then a dedicated NTP time server that receives the time from an atomic clock source should be used.

Network Time Protocol Time Synchronisation Made Easy

  |   By

One of the most important aspects of networking is keeping all devices synchronised to the correct time. Incorrect network time and lack of synchronisation can play havoc with system processes and can lead to untold errors and problems debugging.

And failing to ensure devices are continually checked to prevent drift can also lead to a synchronised network slowly becoming unsynchronised and leading to the kinds of problems aforementioned.

However, ensuring a network not only has the correct time but that that time is not drifting is achieved using the time protocol NTP.

Network Time Protocol (NTP) is not the only time synchronisation protocol but it is by far the most widely used. It is an open source protocol but is continually updated by a large community of Internet time keepers.

NTP is based around an algorithm that can work out the correct and most accurate time from a range of sources. NTP allows a single time source to be used by a network of hundreds and thousands of machines and it can keep each one accurate to that time source to within a few milliseconds.

The easiest way of synchronising a network with NTP is to use a NTP time server, also known as a network time server.

NTP servers use an external source of time, either from the GPS network (Global Positioning System), or from broadcasts from national physics laboratories such as NIST in the US or NPL in the UK.

These time signals are generated by atomic clocks which are many times more accurate than the clocks on computers and servers. NTP will distribute this atomic clock time to all devices on a network it will then keep checking each device to ensure there is no drift and correcting the device if there is.

Europes GPS System is starting to Take Shape

  |   By

Following years of wrangling and uncertainty, the European equivalent to the GPS (Global Positioning System), is finally beginning to take shape. The European Galileo system, which will complement the current USA system, is a step closer to completion.

Galileo, which will be the first operational global navigational satellite system (GNSS) outside the United States will provide positioning information for satellite navigation machines and timing information for GPS NTP servers (Network Time Protocol).

The system, being designed and manufactured by the European Space Agency (ESA) and the European Union (EU) and when it is operational it is expected to improve the availability and accuracy of timing and navigation signals transmitted from space.

They system has been dogged in political wrangling and uncertainty since its inception nearly a decade ago. Objections from the US that they will lose the ability top switch off GPS in times of military need; and economic restraints across Europe, meant that the project was nearly shelved several times.

However, the first four satellites are being finalised in a laboratory in southern England. These In-Orbit Validation (IOV) satellites will form a mini-constellation in the sky and prove the Galileo concept by transmitting the first signals so the European system can become a reality.

The rest of the satellite network should follow shortly after and. Galileo should eventually comprise over 30 of them which means that users of satellite navigation systems of GPS NTP time servers should get quicker fixes be able to locate their positions with an error of one metre compared with the current GPS-only error of five.

Auditable Time Synchronization with an NTP Server

  |   By

Time synchronization is crucial for many modern applications. Whilst computer networks all have to be running in perfect time to prevent errors and ensure security other systems require time synchronization for legal reasons.

Average speed cameras, traffic light cameras, CCTV, parking meters and alarm systems to name but a few, all require accurate time synchronization not just to ensure the correct operation of the systems but also to provide an auditable and legal trail for use in prosecutions.

Failure to do so can lead to the system being completely useless as any legal case based around the technology would need to be provable.

For instance, a CCTV network that is not synchronized would not be admissible in court, a defendant could easily claim that an image of them on a camera could not be them as they were not in the vicinity at the time and unless the camera system can be audited and proved to be accurate then reasonable doubt would see any case against the suspect dropped.

For this reason, systems like those mentioned above require complete auditable time synchronisation that can be proven beyond reasonable doubt in a court system.

An auditable system of time synchronization is only possible by using a dedicated NTP time server (Network Time Protocol). NTP servers not only provide an accurate method of synchronization being accurate to a few milliseconds they also provide a full audit trail that can’t be disputed.

NTP server systems use the GPS network or specialist radio transmissions to receive the atomic clock time which is so accurate the chance of it being even a second out from UTC time (Universal Coordinated Time) is over 3 billion to one which is even greater than the accuracy of other legal evidences such as DNA.

GPS Atomic Clock Time Signals

  |   By

It seems that nearly every car dashboard has a GPS receiver perched on the top. They have become incredibly popular as a navigational tool with many people relying on them solely to work their way around the road networks.

The Global Positioning System has been around for quite a few years now but was originally designed and built for US military applications but was extended for civilian use following an airline disaster.

Whilst it is incredibly useful and convenient a tool, the GPS systems is relatively simple in its operation. The navigation works using a constellation of 30 or so satellites (there are quite a few more that are orbiting but no longer operational).

The signals sent from the satellites contain three pieces of information that are received by the sat nav devices in our cars.

That information includes:

* The time the message was sent

* The orbital position of the satellite (known as the ephemeris)

* The general system health and orbits of the other GPS satellites (known as the almanac)

The way the navigational information is worked out is by using the information from four satellites. The time the signals left the each of the satellites is recorded by the sat nav receiver and the distance from each satellite is then worked out using this information. By using the information from four satellites it possible to work out exactly where the satellite receiver is, this process is known as triangulation.

However, working out exactly where you are in the world does rely on complete accuracy in the time signals that are broadcast by the satellites. As signals such as the GPS travel at the speed of light (approximately 300,000 km a second through a vacuum) even a one second inaccuracy could see positioning information out by 300 kilometres! Currently the GPS system is accurate to five metres which demonstrates just how accurate the timing information broadcast by the satellites is.

This high level of accuracy is possible because each GPS satellite contains atomic clocks. Atomic clocks are incredibly accurate relying on the unwavering oscillations of atoms to keep time – in fact each GPS satellite will run for over a million years before it will drift by as much as a second (compared to the average electronic watch which will drift by a second in a week or two)

Because of this high level of accuracy the atomic clocks on board GPS satellites can be used as a source of accurate time for the synchronization of computer networks and other devices that require synchronization.

Receiving this time signal requires the use of a NTP GPS server that will synchronize with the satellite and distribute the time to all devices on a network.

Why Bother Using a NTP Time Server?

  |   By

Keeping computers synchronized on a network is vitally important, especially if the network in question deals with time sensitive transactions. And failing to keep a network synchronized can cause havoc leading to errors, vulnerabilities and endless problems with debugging.

However with the amount of online time servers available from reputable places such as NIST or Microsoft it is often queried as to why computer networks need to be synchronised to an external NTP time server.

These dedicated NTP devices are often seen as an unnecessary expense and many network administrators simply forgo them and connect to an online time server, after-all, it does the same job doesn’t it?

Actually there are two major reasons why NTP time servers are not only important but essential for most computer networks and to overlook them could be costly in many ways.

Let me explain. The first reason why an external NTP server is important is accuracy. It’s not that internet time sources are generally inaccurate (although many are) but there is the question of distance the time reference has to travel. Furthermore, in times when the connection is lost -whether it’s because of a local connection fault or the time server itself goes down – the network will start to drift until the connection is restored.

Secondly and perhaps most important is the security issues involved in using an Internet time source. The main problem is that if your connection to a time server through the then a open port (UDP 123 fro NTP requests) has to be left open, And as with any open port that can used as a gateway for malicious software and users.

The reason dedicated NTP time servers are essential for computer networks is that they work completely independently and external to the network’s firewall. Instead of accessing a time source across the Internet they use either GPS or radio transmissions to get the time. And in doing so they can provide accurate time all the time without fear of losing a connection or allowing a nasty Trojan through the firewall.

When Time is Money Accuracy Matters

  |   By

We live in a fast paced world where time matters. In some industries even a second can make all the difference. Millions of dollars are exchanged hands in the stock exchange each second and share prices can rise or plummet.

Getting the right price at the right time is essential for trading in such a fast paced money market and perfect network time synchronization is the essential to be able to make that happen.

Ensuring every machine that deals in stocks, shares and bonds has the correct time is vital if people are going to trade in the derivatives market but when traders are sat in different parts of the world how can this possibly be achieved.

Fortunately Coordinated Universal Time (UTC), a global timescale developed after the development of atomic clocks, allows the same time to govern every trader, regardless of where they are in the world.

As UTC is based on atomic clock time and is kept accurate by a constellation of these clocks, it is high reliable and accurate. And industries like the stock exchange use UTC to govern the time on their computer networks.

Computer network time synchronization is achieved in computer networks by using the NTP server (Network Time Protocol). NTP servers receive a source of UTC from an atomic clock reference. This is either from the GPS network or through specialist radio transmissions (it is available through the internet too but is not as reliable).

Once received, the NTP server distributes the highly accurate time throughout the network, continually checking each device and workstation to ensure the clock is as precise as possible.

These network time servers can keep entire networks of hundreds and thousands of machines in perfect synchronization – to within a few milliseconds of UTC!

Time Synchronization on Windows 7

  |   By

Windows 7, the latest operating system from Microsoft is also their first operating system that automatically synchronizes the PC clock to an internet source of UTC time (Coordinated Universal Time). From the moment a Windows 7 computer is switched on and is connected to the Internet it will request time signals from the Microsoft time service – time.windows.com.

While for many home users this will save them the hassle of setting and correcting their clock as it drifts, for business users it may be problematic as internet time sources are not secure and receiving a time source through the UDP port on the firewall could lead to security breaches and as Internet time sources can’t be authenticated by NTP (Network Time Protocol) the signals can be hijacked by malicious users.

This internet time source can be deactivated by opening the clock and date dialogue box, and opening the Internet Time tab, clicking the ’Change’ setting button and unchecking the ‘Synchronize with an Internet time server< option.’

Whilst this will unsure no unwanted traffic will be coming through your firewall it will also mean that the Windows 7 machine will not be synchronised to UTC and its timekeeping will be reliant on the motherboard clock, which will eventually drift.

To synchronize a network of Windows 7 machines to an accurate and secure source of UTC then the most practical and simplest solution is to plug in a dedicated NTP time server. These connect directly to a router or switch and enable the safe receiving of an atomic clock time source.

NTP time servers use the highly accurate and secure GPS signal (Global Positioning System) available everywhere on the planet or more localized long wave radio signals transmitted by several national physics laboratories such as NIST and NPL.

Choosing a Time Source for UTC Synchronization

  |   By

Ensuring a computer network is time synchronized is vital in modern computer networks. Synchronization, not just between different machines on a network, but also each computer network that communicates with other networks needs to be synchronized with them too.

UTC (Coordinated Universal Time) is a global timescale that allows networks on other sides of the globe to be synchronized together. Synchronizing a network to UTC is relatively straightforward thanks to NTP (Network Time Protocol) the software protocol designed for this very purpose.

Most operating systems, including the latest Microsoft incarnation Windows 7, have a version of NTP (often in a simplified form known as SNTP), that allows a single time source to be used to synchronize every computer and device on a network.

Selecting a source for this time reference is the only real difficulty in synchronizing a network. There are three main locations where UTC time can accurately be received from:

Internet Time

There are many sources of internet time and the latest version of Windows (Windows 7) automatically synchronizes to Microsoft’s time server time.windows.com, so if Internet time is adequate Windows 7 users need not alter their settings. However, for computer networks where security is an issue then internet time sources can leave a system vulnerable as the time has to be received through the firewall forcing a UDP port to be left open. This can be utilised by malicious users. Furthermore, there is no authentication with an internet time source so the timecode could be hijacked before it arrives at your network.

GPS Time

Available literally everywhere on the globe, GPS provides a 24-hour, 365 days-a-year source of UTC time. Delivered externally to the firewall via the GPS satellite signal, time synchronization with GPS is accurate and secure.

Radio Transmissions

Usually broadcast by national physics laboratories such as NIST in the US and the UK’s NPL, the time signals are received via longwave and are also external to the firewall so are secure and accurate.

A dedicated NTP time server can receive both radio and GPS time signal guaranteeing accuracy and security.

Configuring a Dedicated NTP Time Server on Windows 7

  |   By

Windows 7 is the very latest operating system from Microsoft. Replacing the rather disappointing Windows Vista, Windows 7 promises to correct the flaws that made its predecessor so unpopular.

One of the changes Windows 7 makes is that it automatically synchronizes the time using the Windows Time service located at windows.time.com. Whilst this is an accurate stratum 2 time server, managed by Microsoft, it can be changed for another source of Internet time. However, even Microsoft recommend that Internet time sources should not used for computer networks as they can’t be authenticated by the time protocol NTP (Network Time protocol). Furthermore, an internet time source needs a port left open in the firewall for the time signals to make it through. Any open port in a firewall can be used by a malicious user to gain access to the network.

For a secure, authenticated and accurate method of synchronizing a Windows 7 network, then it is wise to use a dedicated network time server. Most of these time servers use the protocol NTP (Network Time Protocol) which can easily distribute a single time server throughout a network of hundreds and even thousands of machines.

Time servers plug directly into the router/switch for the network or can be installed on a single machine. Rather than rely on the Internet for a source of time and risk leaving the firewalls UDP port open, dedicated NTP time servers use either the GPS signals or long wave radio broadcasts transmitted from national physics laboratories such as the MSF signal broadcast by the UK’s NPL and the USA WWVB signal broadcast by NIST.

As these signals are external to the firewall and are able to be authenticated by NTP to establish the authority of the signals and are a more accurate and secure method of synchronizing a Windows 7 network.