How do VPNs work? The Ultimate Guide

What is a VPN?

A VPN, Virtual Private Network, is a secure tunnel between two or more devices. VPNs protect personal data, avoid online censorship, and unblock websites. When you connect to a VPN, all of your traffic is encrypted and routed through a secure server. This makes it almost impossible for anyone to track your location or intercept traffic. VPNs can bypass geo-restrictions and access websites that would otherwise be unavailable. For example, a VPN can access Netflix from another country. VPNs can often block ads and scan for viruses to provide an extra layer of protection.

When you connect to the internet through a VPN, your traffic is routed through that server. This has several advantages. First, your ISP (Internet Service Provider) cannot see what you are doing online. Second, it helps to protect you from malicious actors on the internet, as your traffic is encrypted and difficult for them to intercept.

Origins of VPN

The genesis of VPN can be traced back to the early days of the internet. In the early 1990s, two computer scientists were working on the way to connect two computers over the internet. They wanted to create a virtual private network or VPN that would allow users to securely exchange information without going through a third party. To do this, they developed a system of encryption that would make it impossible for anyone to intercept or read the data passing between the two computers. The first VPN was born.

Since then, VPN has come a long way. Today, dozens of different VPN providers offer a wide range of features and services. But at its core, VPN is still about creating a secure, private connection between two devices. So whether you're using it to stream your favorite shows or keep your data safe from prying eyes, VPN is essential for anyone who wants to stay connected.


We have used the word encrypted already several times but didn’t explain it yet, so here we go.

When you connect to a VPN, encryption protects your data as it travels from your device to the VPN server. Encryption is a process of transforming readable data into an unreadable format. This makes it very difficult for anyone who intercepts your data to read. A VPN uses a combination of encryption algorithms to protect your data. The most common encryption algorithms are AES-256, Blowfish, and 3DES. Encryption works by using a public key and a private key. The public key is used to encrypt data, and the private key is used to decrypt it.


AES-256 is a type of encryption that uses a 256-bit key to encrypt and decrypt data. This key size is considered to be very secure, and it would take billions of years to exhaust all possible keys using current computers. However, it is important to remember that encryption can always be broken, given enough time and resources. In addition, encryption can also be circumvented if the private key is compromised. For this reason, it is essential to choose encryption methods carefully and to keep private keys safe.


A blowfish is a symmetric-key block cipher that can be used to encrypt data. The algorithm was developed by Bruce Schneier in 1993, and it is named after the fish because of the way it expands and contracts its body to protect itself. The blowfish algorithm is designed to be resistant to brute force attacks, and it has been used in a number of commercial products. The key length can be any multiple of 8, up to 448 bits. The Blowfish algorithm is faster than DES and does not suffer from the same security vulnerabilities. The main disadvantage of the algorithm is that it requires more computational power than other algorithms.

Triple DES

Triple DES or 3DES is a type of encryption that uses three keys to encrypt and decrypt data. 3DES is a stronger form of encryption than standard DES encryption but is also slower. 3DES encryption is used in some VPNs to provide extra security for sensitive data.

Encryption summary

The strength of an encryption cipher depends on several factors, including the length of the key and the complexity of the algorithm. The longer the key, the more difficult it is to break the cipher. Current computers can brute force some shorter keys, but longer keys are infeasible to break without a major breakthrough in computing power. The cipher algorithms themselves can also be attacked, but this is generally much harder than breaking the key. With current technology, it is possible to break some weaker ciphers, but strong ciphers are secure against all known attacks.

Overall, modern encryption is quite secure. Strong cipher algorithms combined with long keys make it infeasible to break even with current computers. However, it is important to remember that no cipher is perfect and that new attacks are always being developed. As computing power increases and new attack methods are discovered, older cipher algorithms may become vulnerable. As a result, it is important to keep up with advances in cryptography in order to maintain the security of our data.


Routing traffic is the process of directing network traffic from one point to another. When you connect to the internet, your computer sends data packets through a series of intermediate networks on their way to their destination. Each time a data packet passes through a network, its routing information is updated so that it can continue on its journey. A VPN works by routing your computer's traffic through a VPN server before it reaches its destination. This has the effect of changing your IP address since your traffic is coming from the VPN server instead of directly from your computer. This can be useful for accessing restricted websites or for hiding your location from people who might be tracking you online. However, routing your traffic through a VPN can also slow down your internet connection, so it's important to choose a proxy wisely.

Setting up a connection with a VPN

When you set up a VPN connection, you're essentially creating a new subnet that only you and the VPN server can access. This is accomplished by encrypting all the traffic between your device and the VPN server, using public and private keys. The traffic is then forwarded through the VPN to its destination. So, when you connect to a VPN, you're creating a secure connection that allows you to exchange traffic only with the VPN server.

Private network

In the early days of the internet, VPNs were created as a way for companies to connect their private networks securely. By encrypting the data passing between the two networks, VPNs prevented eavesdroppers from being able to access sensitive information. Today, VPNs are still used by businesses to protect their data, but they have also become a popular way for individuals to secure their internet connection.

Nowadays, a VPN is more likely to refer to the proxy server, a gateway between you and the internet. It turns out that "private network" doesn't really describe what most VPNs are used for these days. There's nothing particularly private about that.

Leaking DNS

DNS, or Domain Name System, is a key part of the internet that helps to convert readable domain names into numerical IP addresses. Whenever you type in a website address, your browser contacts a DNS server to find the corresponding IP address. However, when using a VPN, your DNS requests should be routed through the VPN server rather than your ISP (just like other internet traffic). This increases your privacy and security.

If forwarding DNS to the VPN server is not set, it can lead to DNS leaks. To ensure that your VPN provider is forwarding DNS requests, you can use a DNS leak test tool to check for any potential problems. There are many websites that allow you to test your DNS for free; It takes only a few seconds to know if your VPN provider is protecting your DNS from leaking.

Server side and client side

A VPN server is a computer that allows other computers to connect to it through a secure, encrypted connection. The primary purpose of a VPN server is to enable remote users to access files and resources on a private network. But more often, you will meet it as a proxy server that encrypts your traffic and route through that server. In this case, you can forget about the private network.

On the other hand, a VPN client is a software program that connects to a VPN server to access the files and resources on the private network (or, as mentioned before, allows you to route your traffic without access to the private network). For a VPN connection to be established, both the VPN server and the VPN client must be configured with the same settings.

While VPN servers and clients are essential for establishing a VPN connection, they each have different roles to play.

As you noticed, you can find two types of VPNs: those designed for business and personal use. Business VPNs typically allow employees to securely connect to the company network to access files and resources, while personal VPNs encrypt internet traffic and improve online privacy. Both types of VPNs have their advantages and disadvantages.

Weak points

While VPNs are often marketed as a way to protect your online privacy, there are some downsides to using these services.
For one thing, VPNs can slow down your internet connection, as your data has to travel through an extra server before reaching its destination.
Additionally, not all VPNs are created equal; some may keep logs of your online activity.
Finally, using a VPN can be a legal grey area in some countries, as it may allow you to bypass government restrictions on internet use.
Ultimately, whether or not a VPN is right depends on your needs and risks. A VPN may be worth the investment if you're concerned about online privacy. However, if you're looking to stream content from another country, there are other (simpler) ways to do so.

Recommended VPNs


NordVPN has an extensive network of servers, so you can always find a fast and reliable connection. Second, the network is stable, so you won't have to worry about dropped connections or other interruptions. Third, NordVPN has excellent customer support, so if you have any questions or problems, you can always get help from a live person. And fourth, NordVPN offers a money-back guarantee program, so if you're unsatisfied with the service, you can always get your money back. Finally, NordVPN has applications for all major platforms, so you can always stay protected, no matter what device you are going to use.


ExpressVPN is a great option. One thing that sets ExpressVPN apart from other providers is its choice of protocols. Whether you're looking for a fast and secure connection or more flexibility, ExpressVPN has you covered. And with servers in over 90 countries, you're sure to find a location that meets your needs. Plus, ExpressVPN is one of the few providers that has been independently audited. This means you can be confident that your data is being handled securely and privately. If you're looking for a VPN provider that shows a consistent commitment to internet privacy and digital freedom, ExpressVPN is definitely worth considering.


If you're looking for a free VPN provider, you can't go wrong with VPN4Test. They offer multiple protocols to choose from, including TPC, UDP, and TOR, so you can always find the right one for your needs. Plus, their double VPN feature ensures that your traffic is always routed through two servers for maximum security. And with over seven years of experience on the market, you can rest assured that VPN4Test is a trustworthy and reliable provider. So why not give them a try today? You won't be disappointed.


  • A VPN is a secure tunnel between two or more devices that uses encryption to protect personal data and unblock websites.
  • VPNs can bypass geo-restrictions and access websites that would otherwise be unavailable.
  • The origins of VPN date back to the early days of the internet, when two computer scientists developed a system of encryption to securely exchange information between two computers.
  • A VPN works by routing your computer's traffic through a VPN server before it reaches its destination, which has the effect of changing your IP address and encrypting your data.
  • Private networks were originally created as a way for businesses to connect their private networks securely. Today, they are also used by individuals to secure their internet connection.
  • Using a VPN has some disadvantages, such as slowing down your internet connection and being a legal grey area in some countries