The Top NTP Servers for Accurate Time Synchronization

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By Vijay Singh Khatri

Before jumping to this article about the Best NTP servers list, we will give you more details about the NTP time server.

What is an NTP server?

NTP stands for network time protocol. This protocol has been developed to synchronize time between two nodes or servers over a LAN (local area network). NTP servers are considered to be the basic elements of the internet.

The NTP is mainly used to handle tools and utilities available on the systems. The tools available on the systems like macOS and Windows require a proper synchronization of time according to the local area network for them to function. Any discrepancy in the time synchronization would lead to issues with the utilities.

NTP focuses on eliminating the disparity between the server’s local time and the client’s local time. In this process, the node sends a signal in the form of UDP to the time-stamped server, and then the server calculates the time from the local clock offset.

For example, in Windows, the feature of internet time works because of the NTP server only. It uses the time pooling and clusters available on the server to set the time on the machine. Similarly, the date and time system preference feature works in macOS.

How does NTP work?

The idea behind the working of NTP is simple; a computer reads up the time using the local clock and synchronizes the time with all the other devices available in the network. This is a simple explanation, but the whole thing works more complicatedly. And for this to be possible, NTP servers come into play. NTP servers are the most widely used servers on the planet, and every major company adheres to NTP servers to synchronize local time on the devices.

The NTP uses the GPS or GPS master clock to read the time and synchronize it. Other less popular mediums for reading the time are the atomic clock, local clock, or another local server. Sometimes it may also use a local connected radio clock.

The main aim of NTP is to synchronize all the local devices using the coordinated universal time, generally known as UTC. The NTP protocol is considered a client-server model but functions more like a peer-to-peer protocol. In this protocol, both ends think of each other as a legit source of time. The peer-to-peer protocol helps in creating a synchronized mechanism of multiple nodes.

The NTP provides a free platform of reference on its homepage that many prominent operating systems use.

The NTP project creates a group of those volunteer computers that provide highly accurate time using the NTP protocol. This is known as the NTP pool. These nodes are divided as per the different geographical zones. This is a highly decentralized system of time servers distributed worldwide. The data is scanned continuously to know the number of computers that are a part of the NTP Pool.

NTP Amplification DDoS attacks

One of the issues that the NTP project is facing is NTP amplification. The world NTP amplification means the DDoS attacks on the computers attached to a certain time server. The attackers use the reflection method to attack the servers. The attacker sends a forged IP packet to the server, and the server may respond. As soon as the attacker receives the response, they can attack the server’s data.

People are facing a lot of issues due to these amplification attacks. The organizations working with the NTP protocol fear this attack the most. Many employers have now started specifying what time the server should be used. They have stopped allowing their employees to use other time servers for security reasons.

Generally, a server doesn’t lack a security mechanism. Rather, the devices lack configuration settings essential for protecting the nodes. If your device’s time is not synchronized properly, attackers may find a weak spot to attack the system.

Best Public NTP Servers

Here are the top NTP servers that are serving as time guides for devices across the globe:

1. Google Public NTP

There is no segment in the technology sector where Google doesn’t have its presence. Google is known for its unique innovations that astonish the world every time.

Google NTP server is a time-synchronized server that uses atomic clocks to synchronize time in devices. Google NTP server is a bit different from the standard time servers. It uses leap-smearing technology, which is not the practice followed in the other time servers. This helps in smoothly inserting leap seconds over a particular period. They have developed very good systems of loads and atomic clocks in the data centers present worldwide, making Google public NTP one of the most prominent time servers in the world.

2. Facebook Public NTP

Facebook is one of the biggest tech companies in the world. Earlier the only perception of this company was that it was a dedicated social networking site. But in reality, it is in all the major horizons of the tech world. Its social networking platform has become a small part of the company’s numerous ventures, and Facebook is now functioning in almost every segment imaginable.

This company has a free NTP server as well. The value that Facebook believes in is that as more computers access the internet, the infrastructure is expanding. Thus, ensuring a more accurate time across all devices has become crucial. After Google, Facebook implemented the leap smearing function to its time server. The leap smearing function involves a layer that smears a leap second out, which it later adds or subtracts in 18 hours.

Facebook has a multi-layered time server infrastructure consisting of satellites with high-precision atomic clocks at the top layer of the stratum. Facebook also employed its atomic clocks to sync with the top layer. This atomic clock server is the second layer. The third layer consists of a huge pool of multiple NTP servers. The leap-smearing technology is implemented here. The last layer consists of multiple servers that can handle many devices and accurately serve time.

3. Cloudfare NTP

Cloudflare is among the top technology companies in the world. This company’s main aim is to make the protocols available for free to the public. It tries to create secured versions of NTPs and distribute them to the public for their usage. It has developed protocols for the public that include HTTPS, NTPs, and several others at no cost. The NTP server for the public is its latest addition to the bundles of protocols.

They have data centers and pool nodes available in around 180 countries that help give accurate time to the local devices. The Cloudflare system tries to reduce the discrepancy in the time synchronization protocols in the network symmetry. Time reversal symmetry is an integral part of a system. Time reversal means that the device’s functions should not change with the change in time. If there are no synchronization protocols, the device dynamics will take a hit as soon as there is a server change. Time reversal symmetry is an integral part of a system. Time reversal means that the device’s functions should not change with the change in time. If there are no synchronization protocols, the device dynamics will take a hit as soon as there is a server change.

With their free NTP server, Cloudflare aims to create a better and more sustainable time server that is safe from DDOS attacks. It also strives to increase the robustness of its time servers and create more data centers for better accuracy of time.

4. Apple NTP Server

The first thing that comes to mind about innovation is Apple. It is renowned for developing the most innovative, classic, and secure technology. Apple has revolutionized the way the world works. One innovation is the Apple NTP server, developed specifically for macOS and iOS.

This NTP server works on similar lines as Cloudflare. However, the only difference is that this server is only available for macOS and iOS devices. By default, Apple’s NTP server is active in the IOS and macOS products. Although, you have the option to change and choose any other public NTP server for your apple device. There is some level of flexibility in terms of server selection. , One of the biggest advantages of using Apple’s NTP server is the security against DDoS attacks. The DDoS attacks are minimal when using the Apple NTP server. This is an added advantage of using Apple devices. We have several parts that mention the DDOS attacks.

5. Microsoft NTP server

The Windows free NTP server does not exactly work like Network Time Protocol (NTP); it uses a complex suite of algorithms slightly different from the standardized set of time servers. These algorithms have been specifically developed to ensure that all the computers work as accurately as possible.

If your device has selected or is using more than a one-time server, then it synchronizes the time of the other servers with its own to provide the most accurate time.

It has also established a system of using volunteer computers from all across the world that works on the P2P protocol to provide accurate time to other nodes available on that local area network. This is where the special algorithm of Microsoft comes into play. As this algorithm starts receiving the samples from different volunteer nodes, it identifies the most accurate time from them. It then uses NTP to synchronize time in all the available devices. You can think of this algorithm as an added mechanism for cross-checking.

Security as a Factor

One of the most important things you should consider while choosing an NTP server is its security. The NTP mentioned above servers are the most secure and best time servers available on the web. We have already mentioned the complexities of security in a time server. Always try to choose those service providers that have established goodwill in the market. For example, Google or Apple, you can stay assured about the security of their NTP servers.

Remote Availability

Many people travel a lot for their work. Thus they must choose a time server that is available in most places around the world. The main issue that arises with less prominent servers is that there are fewer pool zones. Thus, it leads to a delay in receiving the time data.


Presently, an NTP server is the best time source for digital devices. It is one of your device’s most secure and perfect synchronizing times. The possibility of a better source can never be eliminated, but this is the best alternative in the technology segment.

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