Useful NTP server related resources

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NTP homepage–  The home for the NTP Project who provides support and additional development resources for the Official Reference Implementation of NTP.

NTP Project support pages

THE NTP pool – list of public servers

NPL – The National Physical Laboratory in the UK who control the MSF radio signal.

The University of Delaware and David Mills’ information page, Professor Mills is the original inventor and developer of NTP

David Mills’ list of Public NTP Time Servers a list of public NTP servers

National Institute of Standards and Technology (NIST) who operate the USA’s WWVB radio signal

Europe’s largest supplier of NTP server related products.

Galleon UK – NTP server products for the UK

NTP Time Server .com  – one of the largest time and frequency suppliers in the United States

NTP – Wikipedia article on NTP

NTP server checker – free tool to ensure time server accuracy

The NTP Server and Accurate Time

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Accurate time on a network is essential for all businesses and institutions. Without an accurately synchronised system a computer network can be vulnerable to all sorts of problems, from malicious hackers and other security threats to fraud and data loss.
Network Time Protocol is the key to keeping accurate time it is a software algorithm that has been constantly developed for over two decades. NTP takes a single time source that is received by the NTP server and distributes it across a network ensuring all machines in that network are running to exact same time.

Whilst NTP can maintain synchronisation of a network to within a few milliseconds it is only as good as the time source it receives. A dedicated NTP server will use a time signal from an external source and so keep the network secure as the firewall will not have to be disturbed.

The two preferred methods for most users of NTP servers is the GPS network (Global Positioning System) or specialist time and frequency transmissions put out be several national physics labs such as the UK’s NPL.

These time signals are UTC (Coordinated Universal Time) which is the world’s civil timescale. An NTP server receiving time source from either a frequency transmission or the GPS network can realistically provide accuracy to within a few milliseconds of UTC

Network time servers are preferred as a synchronisation tool rather than the much simpler internet time servers because they are far more secure. Using the internet as a basis for time information would mean using a source outside the firewall which could allow malicious users to take advantage.

Network time servers on the other hand work inside the firewall, both of these type of signals are incredibly accurate and secure with each method providing millisecond accuracy to UTC. However, there are downsides to both systems. The radio signals broadcast by nation time and frequency laboratories are susceptible to interference and locality, while the GPS signal, although available literally everywhere on the globe can occasional be lost too (often due to bad weather interfering with the line-of-sight GPS signals.

For computer networks where high levels of accuracy are imperative, dual systems are often incorporated. These dual network time servers receive the time signal from both the GPS network and the radio transmissions and select an average for even more accuracy.  However, the real advantage of using a dual system is that if one signal fails, for what ever the reason, the network will not have to rely on the inaccurate system clocks as the other method of receiving UTC time should still be operational.

Does My Business Need Accurate Time Synchronisation Five question (part 2)

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Keeping accurate time on a network with a NTP time server is highly important here is the second part of the article that explains why.

Legal protection – Whether it is a payment dispute with a supplier or customer or even a case of fraud committed against your company only an accurate method of synchronisation will be accepted as a legal defence. An NTP time server is legally auditable and can be used as evidence in a court of law.

Company Credibility:
Being victim to any of these potential hazards can have devastating effects on your own business but also that of your suppliers and customers. Once word gets out too it will soon become common knowledge amongst your competitors, customers and suppliers as news travels quickly in the business world. Keeping credibility is a good enough reason in itself to ensure a computer network is adequately synchronised.

If you have answered yes to any of the above questions then it is time your company invested in a dedicated NTP time server to accurately synchronise you computer network to.  Dedicated time servers use the protocol NTP (Network Time Protocol) as a method of distributing a single time source around the internet. UTC (Coordinated Universal Time) is the preferred time standard that most networks are synchronised to.

An NTP time server can receive a secure and accurate UTC time signal from the GPS network or from long wave radio transmissions broadcast by several national physics laboratories.

Does My Business Need Accurate Time Synchronisation Five question (part 1)

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Time synchronisation can be crucial for many computer networks. Correct synchronisation can protect a system from all sorts of security threats it will also ensure that the network is accurate and reliable but are dedicated NTP time server systems really necessary or can a network be run securely without a network time server?

Here are five questions to ask yourself to see if your network needs to be adequately synchronised.

1.  Does your network conduct time sensitive transactions across the internet?

If yes then accurate network time synchronisation is essential. Time is the only point of reference a computer has to identify two events so when it comes to a transaction across the internet such as sending an email, if it comes from an unsynchronised network, it may arrive before it was technically sent. This may lead to the email not being received as a computer cannot handle negative values when it comes to time.

2. Do you store valuable data?

Data loss is another ramification of not having a synchronised network. When a computer stores data it is stamped with the time. If that time is from an unsynchronised machine on a network then a computer may consider the data already saved or it may overwrite new data with older versions.

3. Is security important to your business and network?

Keeping a network secure is essential if you have any sensitive data on the machines. Malicious users have a myriad of ways of gaining access to computer networks and using the chaos caused by an unsynchronised network is one method they frequently take advantage of. Not having a synchronised network may mean it is impossible to identify if your network has been hacked into too as all records left on log files are time reliant too.

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.