Category: NTP Basics

NTP Server Time Tired of Inaccurate and Insecure Time

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The internet has been a marvellous resource for business over the last decade. High speed access and the proliferation of computers in homes and offices alike have turned the World Wide Web into the main business arena for many companies.

With more and more transactions being conducted from opposite ends of the world across the internet, the need for an accurate and precise clock to keep computer networks synchronised has never been greater.

Most of the world’s computer networks, synchronise to a source of UTC (Coordinated Universal Time) which is the worldwide standard and is controlled by atomic clocks. A worldwide standard for synchronising the clocks has been developed also. NTP (Network Time Protocol) is a software algorithm that distributes UTC amongst a network’s clocks and adjusts the time accordingly.

Many computer network administrators turn to the internet as a source of NTP server time as there are a multitude of sources of UTC time. However, many internet sources of NTP time cannot be relied upon to provide accurate time. Surveys have discovered more than half of all internet time servers were inaccurate by over a second and even those that are not, they could be too far away to provide any useful precision.

More importantly, however, is that internet based NTP servers are external to a network’s firewall so any regular communication with a NTP server will require the firewall port to be left open allowing easy access for malicious users to take advantage of.

The only solution for getting a source of NTP server time, whilst keeping a network secure, is to use an external stratum 1 NTP time server. These devices communicate directly with an atomic clock either via the GPS satellite network or long wave radio signals. Because these devices operate from with the firewall the entire network is kept secure whilst the NTP server distributes an accurate, precise and source of UTC time.

Using Time and Frequency Transmissions to Synchronise a Computer Network

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Computer network synchronisation is often perceived as a headache for many system administrators but keeping accurate time is essential for any network to remain secure and reliable. Failing to have an accurate synchronised network can lead to all sorts of errors when dealing with time sensitive transactions.

The protocol NTP (Network Time Protocol) is the industry standard for time synchronisation. NTP distributes a single time source to an entire network ensuring all machines are running the exact same time.

One of the most problematic areas in synchronising a network is in the selection of the time source. Obviously if you are spending time getting a network synchronised then the time source would have to be a UTC (Coordinated Universal Time) as this is the global timescale used by computer networks all over the world.

UTC is available across the internet of course but internet time sources are not only notoriously inaccurate but using the internet as a time source will leave computer system open to security threats as the source is external to the firewall.

A far better and secure method is to use a dedicated NTP time server. The NTP server sits inside the firewall and can receive a secure time signal from highly accurate sources. The most commonly used these days is the GPS network (Global Positioning System) this is because the GPS system is available literally anywhere on the planet. Unfortunately it does require a clear view of the sky to ensure the GPS NTP server can ‘see’ the satellite.

There is another alternative however, and that is to use the national time and frequency transmissions broadcast by several national physics laboratories. These have the advantage in that being long wave signals they can be received indoors. Although it must be noted these signals are not broadcast in every country and the range is finite and susceptible to interference and geographical features.

Some of the main transmissions broadcast are known as: the UK’s MSF signal, Germany’s DCF-77 and the USA’s WWVB.

Using GPS to Synchronise Network Time

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The global positioning system has been around since the 1980’s. It was designed and built by the United States Military who wanted an accurate positioning system for battlefield situations. However, following the accidental shooting down or a Korean airliner, the then US president (Ronald Reagan) agreed that the system should be allowed to be used by civilians as a way of preventing such a disaster from occurring again.

From then on the system has broadcast in to two frequencies L2 for the US Military and L1 for civilian use. The system works by using ultra precise atomic clocks that are on board each satellite. The GPS transmission is a timecode produced from this clock combined with information such as the position and velocity of the satellite. This information is then picked up by the satellite navigation receiver that calculates how long the message took to reach it and therefore how far from the satellite it is.

By using triangulation (use of three of these signals) the exact position on Earth of the GPS receiver can be ascertained. Because the speed of the transmissions, like all radio signals, travels at the speed of light it is highly important that the GPS clocks are ultra-precise. Just one second of inaccuracy is enough to make the navigational unit inaccurate to over 100,000 miles as light can travel such vast distances in such a short space of time.

Because GPS clocks have such a high level of accuracy it means they also have another use. The GPS signal, being available anywhere on the planet, is a highly efficient means of getting a time signal to synchronise a computer network too. A dedicated GPS time server will receive the GPS signal then convert the atomic time signal from it (known as GPS time) and convert it to UTC (Coordinated Universal Time) which is simple to do as both timescales are based on International Atomic Time (TAI) and the only difference being GPS time does not account for leap seconds meaning it is ‘exactly’ 15 seconds faster.

A GPS time server will most likely use the protocol NTP (Network Time Protocol) to distribute the time to a network. NTP is by far the most commonly used network time protocol and is installed in most dedicated time servers and a version is also included in most Windows and Linux operating systems.

UTC and Global Synchronisation

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A global economy has many benefits allowing trade and commerce to be conducted relatively pain free from the other sides of the planet. But conducting business with other countries can have its problems most notably time differences.

We are used to the fact that when we go to bed in Europe, those in Australasia are jest getting up and for many businesses, knowing the time in the country that you trade in is essential. However many global transactions are now conducted online and quite often completely automated.

For this reason computers need to know the exact time too, particularly if they are selling products and services that have a limited quantity and any miscalculation in the time can cause untold errors. For instance, if people across the globe wish to buy an airline ticket from an American broker then the computer needs to know who ordered the seat first otherwise there could be a risk of double-booking.

For this reason a global timescale has been developed allowing the whole world to synchronise to one timescale. This global timescale is commonly known as UTC (Coordinated Universal Time) and is based onthe old timescale GMT (Greenwich Meantime) although it accounts for the slowing of the Earth due to tidal and lunar forces.

UTC is kept accurate by atomic clocks that boast an accuracy of a second every 100 million years, however, atomic clocks are highly expensive to own, operate and run and are therefore impractical for a business that just wants to keep accurate UTC.

For this reason the dedicated NTP time server has been developed that can receive a transmitted time signal from an atomic clock and synchronise an entire computer network to it.

The NTP time server can receive a time signal directly from a physic laboratory using a long wave receiver or more conveniently using the GPS signals that are transmitted by satellites 30,000 km above the Earth.

By using a NTP time server a business network can be kept to within a few milliseconds of UTC (thousandth of seconds) ensuring that they can trade and do business with complete and accurate synchronisation.

Selecting a Time Source for a Network Time Server

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UTC – Coordinated Universal Time (from the French: Universel Temps Coordonné) is a global timescale based on Greenwich Meantime (GMT – from the Greenwich Meridian line where the sun is above at 12 noon). But accounts for the natural slowing of the Earth’s rotation. It is used globally in commerce, computer networks via a NTP server, air-traffic control and the World’s stock exchanges to name but a few of its applications.

UTC is really the only solution for time synchronisation needs. While it is just as possible to synchronise a computer network with an NTP server to a time other than UTC it is pointless. As UTC is utilised by computer networks all across the globe by using a UTC time source that means your network can synchronise with every other network in the world that is synchronised to UTC.

UTC is most commonly received from across the Internet, however, this can only be recommended for small network users where either accuracy or security is an issue. An Internet based UTC source is external to the firewall so will leave a potential hole for malicious users to exploit.

Two secure methods of receiving UTC are commonly available. These are either the GPS network (Global Positioning System) or specialist radio transmission broadcast on long wave from several of the world’s national physics laboratories. The two methods have both advantages and disadvantages which need to be ascertained before a method is selected.

A radio transmission such as the UK’s MSF, the German DCF-77 or the USA’s WWVB signal are vulnerable to local topography although many of these signals can be picked up indoors. Whilst not every country transmits a UTC radio signal around the neighbouring countries that do it is possible to still receive it.

GPS on the other hand is available literally anywhere on the globe. The signal comes directly from above and as long as the antenna has a good clear view of the sky it can be received anywhere. However, as the antenna has to be on a roof looking up this can have logistical problems (particularly for very tall buildings).

Specialist dedicated network time servers are available that can actually receive both methods of UTC but whether using GPS or a radio transmissions synchronisation of a network to within a few milliseconds is possible.

Does your Business Need a NTP time server? Five Questions to Ask Yourself

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1. The business world is now more global than ever with as much likelihood of  your customer’s being from the other side of the planet as from around the corner. Any transactions conducted virtually across the Internet require adequate time synchronisation otherwise your company can be open to abuse or fraud, customers may claim they paid you at a certain time but how do you ascertain if they have without adequate synchronisation?

2. Does your system conduct time sensitive transactions? Computers have only one reference between events and that is time. If a network is not synchronised then many events and transactions may fail to happen. This can have a knock-on effect as one transaction or event fails so do others and without adequate synchronisation it may be quite a while before anyone realises the errors.

3. Do you have valuable or sensitive data? A lack of synchronisation can often lead to data loss. Storage and retrieval is also time reliant so if a computer believes the time data should have been saved has past then it may assume the data is already saved. The problem can be exaggerated if the data is continually updated as the inaccurate timestamps may mean that certain updates are not completed.

4. Is security important to your business? A lack of time synchronisation can leave a computer network open to malicious users, hackers and even fraud. If computers on a network are running different times then this can be exploited by malicious users and without time synchronisation you may not even know they have been there. A perfectly synchronised network will also offer legal protection with a NTP server (Network Time Protocol) being auditable and unquestioned in a court of law.

5. Is the credibility of your company important? A lack of synchronisation can be extremely costly not just in time and money but also in the credibility of your company. Without synchronisation a network will be vulnerable to mistakes and while these may be easily rectified once a customer has to complain word will soon get out.

Running a synchronised network adhering to Universal Coordinated Time (UTC) the world’s standard timescale is fairly simple. Dedicated NTP time servers that receive a UTC time source from either a radio transmission or the GPS network (Global Positioning System).are readily available, simple to set up, accurate and secure.

(UTC) Coordinated Universal Time is The only time you will ever need to know

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We may think of their being only one time and therefore one timescale. Sure, we’re all aware of time zones where the clock has to be pushed back an hour but we all obey the same time surely?

Well actually we don’t. There are numerous different timescales all developed for different reasons are too numerous to mention them all but it wasn’t until the nineteenth century that the idea of a single timescale, used y everybody came into effect.

It was the advent of the railway that provoked the first national timescale in the UK (Railway time) before then people would use noon as a basis for time and set their clocks to it. It rarely mattered if your watch was five minutes faster than your neighbours but the invention of the trains and the railway timetable soon changed all that.

The railway timetable was only useful if people all used the same time scale. A train leaving at 10.am would be missed if a watch was five minutes slow so synchronisation of time became a new obsession.

Following railway time a more global timescale was developed GMT (Greenwich Meantime) which was based on the Sun’s position at noon which fell over the Greenwich Meridian line (0 degrees longitude). It was decided during a world conference in 1884 that a single world meridian should replace the numerous one’s already in existence. London was perhaps the most successful city in the world so it was decided the best place for it.

GMT allowed the entire world to synchronise to the same time and while nations altered their clocks to adjust for time-zones their time was always based on GMT.

GMT proved a successful development and remained the world’s global timescale until the 1970’s. By then that atomic clock had been developed and it was discovered in the use of these devices that Earth’s rotation wasn’t a reliable measure to base our time on as it actually alters day by day (albeit by fractions of a second).

Because of this a new timescale was developed called UTC (Coordinated Universal Time). UTC is based on GMT but allows for the slowing of the Earth’s rotation by adding additional ‘Leap Seconds’ to ensure that Noon remains on the Greenwich Meridian.

UTC is now used all over the World and is essential for applications such as air traffic control, satellite navigation and the Internet. In fact computer networks across the globe are synchronised to UTC using NTP time servers (Network Time Protocol). UTC is governed by a constellation of atomic clocks controlled by national physics laboratories such as NIST (National Institute of Standards and Time) and the UK’s NPL.

NTP Server 5 Steps to Network Synchronisation

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Synchronising a network is often considered a headache by network administrators who fear that getting it wrong can lead to disastrous results and while there is no deny that a lack of synchronisation can cause unforeseen problems particularly with time sensitive transactions and security, perfect synchronisation is simple if these steps are followed:

1. Use a dedicated NTP server. The NTP server is a device that receives a single time source then distributes it amongst a network of computers using the protocol NTP (Network Time Protocol) one of the oldest Internet based protocols and by far the most widely used time synchronisation software. NTP is often packaged with modern operating systems such as Windows or Linux although there is no substitute for a dedicated NTP device.

2. Always use a UTC time source (Coordinated Universal Time). UTC is based on GMT (Greenwich Meantime) and International Atomic Time (TAI) and is highly accurate. UTC is used by computer networks all over the world ensuring that commerce and trade are all using the same timescale.

3. Use a secure an accurate time signal. Whilst time signals are available all over the Internet they are unpredictable in their accuracy and while some may offer decent enough precision an Internet time server is outside a networks firewall which if left open to receive a timecode will cause vulnerabilities in the security of the network. Either GPS (global positioning system) or a dedicated radio signal such as those transmitted by national physics laboratories (such as MSF – UK, WWVB – USA, DCF –Germany) offer secure and reliable methods of receiving a secure and accurate time signal.

4. Organise a network into stratum, levels. Strata ensure that the NTP server is not inundated with time requests and that the network bandwidth doesn’t become congested. A stratum tree is organised by a few select machines being stratum 2 devices in that they receive a time signal from the NTP server (stratum 1 device) these in turn distribute the time to other devices (stratum 3) and so on.

5. Ensure all machines are utilising UTC and the NTP server tree. A common error in time synchronisation is to not ensure all machines are properly synchronised, just one machine running inaccurate time can have unforeseen consequences.

The NTP Server Time Synchronisation Made Easy

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Time synchronisation is often described as a ‘headache’ by network administrators. Keeping computers on a network all running the same time is increasingly important in modern network communications particularly if a network has to communicate with another network running independently.

For this reason UTC (Coordinated Universal Time) has been developed to ensure all networks are running the same accurate timescale. UTC is based on the time told by atomic clocks so it is highly precise, never losing even a second. Network time synchronisation is however, relatively straight forward thanks to the protocol NTP (Network Time Protocol).

UTC time sources are widely available with over a thousand online stratum 1 servers available on the Internet. The stratum level describes how far away a time server is to an atomic clock (an atomic clock that generates UTC is known as a stratum 0 device). Most time servers available on the Internet are in fact not stratum 1 devices but stratum in that they get their time from a device that in turn receives the UTC time signal.

For many applications this can be accurate enough but as these timing sources are on the Internet there is very little you can do to ensure both their accuracy and their precision. In fact even if an Internet source is highly accurate the distance away form it can cause delays int eh time signal.

Internet time sources are also unsecure as they are situated outside of the firewall forcing the network to be left open for the time requests. For this reason network administrators serious about time synchronisation opt to use their own external stratum 1 server.

These devices, often called a NTP server, receive a UTC time source from a trusted and secure source such as a GPS satellite then distribute it amongst the network. The NTP server is far more secure than an Internet based time source and are relatively inexpensive and highly accurate.

The NTP Server and the Atomic Clock Reason for Precision

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In an age of atomic clocks and the NTP server time keeping is now more accurate then ever with ever increasing precision having allowed many of the technologies and systems we now take for granted.

Whilst timekeeping has always been a preoccupation of mankind, it has only been in the last few decades that true accuracy has been possible thanks to the advent of the atomic clock.

Before atomic time, electrical oscillators like those found in the average digital watch were the most accurate measure of time and whilst electronic clocks like these are far more precise than their predecessors – the mechanical clocks, they can still drift by up to a second a week.

But why does time need to be so precise, after all, how important can a second be? In the day-to-day running of our lives a second isn’t that important and electronic clocks (and even mechanical ones) provide adequate timekeeping for our needs.

In our day-to-day lives a second makes little difference but in many modern applications a second can be an age.

Modern satellite navigation is one example. These devices can pinpoint a location anywhere on earth to within a few metres. Yet they can only do this because of the ultra-precise nature of the atomic clocks that control the system as the time signal sent from the navigation satellites travels at the speed of light which is nearly 300,000 km a second.

As light can travel such a vast distance in a second any atomic clock governing a satellite navigation system that was just one second out it would the positioning would be inaccurate by thousands of miles, rendering the positioning system useless.

There are many other technologies that require similar accuracy and also many of the ways we trade and communicate. Stocks and shares fluctuate up and down every second and global trade requires that everybody all over the world has to communicate using the same time.

Most computer networks are controlled by using a NTP server (Network Time Protocol). These devices allow computer networks to all use the same atomic clock based timescale UTC (coordinated universal time). By utilising UTC via a NTP server, computer networks can be synchronised to within a few milliseconds of each other.