Close this search box.

VPN Glossary: Technical Terminology Made Simple

With so many technical terms, it’s sometimes difficult to fully understand what some VPN service providers or even VPN experts are trying to communicate.

So, to help you out, we’ve collected the most important VPN terms and created this easily comprehensible VPN glossary.

I hope you find it to be useful.

Ad Blocker

As the name suggests, an Ad blocker is a tool that blocks those annoying ads that pop up anytime you visit a website.

It can be a standalone tool like the Adblock Plus, or it can come as an extra feature with VPN service providers like NordVPN, Surfshark, CyberGhost, Windscribe, etc.

It’s a necessary security tool because it shields you from the ads that are not only annoying but are also potential malware or data-collecting tools.

AES (Advanced Encryption Standard)

AES is an encryption cipher that VPNs use it to make sure that your online activity stays hidden from prying eyes.

It’s currently the most trustworthy encryption standard, used even by the United States federal government. Hence, the term “military-grade” encryption.

AES is a symmetrical key cipher, which means it uses one ‘key’ to both encrypt and decrypt data.

Its key sizes are 128-bit, 192-bit, and 256-bit, which represents the number of rows that your data goes through to get encrypted.

The higher the number, the harder it is for someone to decrypt the data, meaning the potential key combination increases with the key size.

For example, a 1-bit key has 2 possible combinations.

The 2-bit has 4, the 4-bit has 16, and the 16-bit has 256 key combinations. Until you get to 256-bit keys, you also reach a total of 1.1 x 10^77 possible key combinations.

Even the most advanced computer would take millions of years to decode it.

In most VPNs these days, you usually find the AES-256, backed up by the OpenVPN protocol, which is an extremely safe combination.

Asymmetric & Symmetric Encryption

There are two types of encryption – symmetric and asymmetric.

An example of symmetric encryption is the AES, which uses a single key for encryption and decryption of data.

The same key is shared between the people/devices that need to receive the message. When used properly symmetric encryption can be incredibly safe, plus it’s much faster.

Asymmetric encryption uses two different (asymmetrical) keys, one for encryption, the other one for decrypting data that travels between two spots.

One key is public, and can only encrypt the data, while the second one, which is private, can only decrypt it.

Without the private key, no one can decrypt the data. Although this can be convenient, if the private key is lost, the data won’t ever be restored.

Asymmetrical encryption is more secure but incredibly complex and much slower. An example is the RSA (Rivest-Shamir-Adleman) encryption protocol, often seen in more advanced VPNs.


Bitcoin was the first and is, currently, the most popular cryptocurrency. It’s a decentralized digital coin that you can use for more anonymous transactions on the internet.

Some VPN service providers allow payments with Bitcoin and other cryptocurrencies.

Bitcoin, like other crypto coins, allows direct transactions without a middle-man, meaning no banks nor government regulation.

It operates on a system called Blockchain, and the transactions are encrypted, making Bitcoin a semi-anonymous payment method (other cryptocurrencies allow for higher anonymity than Bitcoin, like Monero).


BitTorrent is a tool (software) that allows you peer-to-peer (P2P) file-sharing.

It works through torrents, and it’s usually used for sharing movies, music, or software.


Censorship on the internet is the act of blocking content and making it unavailable for (certain) users.

It is usually done by governments, as a way to control what the public eye has access to and how they use this information.

The most prominent problem with online censorship can be traced to countries like China, Russia, Turkey, UAE, and Middle-East countries.


A cipher or cypher is a computer algorithm (a sequence that performs computer-given instructions) used for encrypting or decrypting something.

Connection Speed

It’s the speed of your VPN server.

When you connect to the internet through a VPN server, the connection speed usually slows down, because your internet traffic does not travel directly from and to the wanted destination, and it’s heavily encrypted.

However, a good VPN should provide you with good connection speed, regardless of the server location.


A website cookie, also known as a computer cookie or magic cookie, represents a small amount of data that websites send to your computer (in your Cookies file), which then the computer sends back to the websites.

The cookies contain information that helps the website track how you use them, to remember your login information, your activity, etc.

Although they might seem a bit intrusive to your privacy, cookies are usually necessary for a better online experience.

Dark Web

The notorious dark web is a “hidden” part of the internet that you can access through a special browser, called the Tor browser.

The dark web is just a portion of the “deep web” which consists of websites that are not indexed by regular search engines, and are often only accessible through a password.

Data Retention

Data retention is the process of data storage for compliance or business reasons.

Most countries have their own policies on data retention backed up by law.

They dictate whether the companies and organizations are obliged to collect and store their users’ data, to what extent, and for how long.

Countries with looser data retention laws are considered to be more privacy-friendly.

DDoS Attacks

DDoS stands for distributed denial-of-service.

It’s a malicious online threat, often seen in gaming, where the attacker compromises your computer (or other network resources and machines) with the intent to use it as a part of a large botnet (a collection of malware-infected devices that allow hackers to control them).

The botnet’s purpose is to overwhelm the target with a flood of internet traffic.

In the case of an undergoing DDoS attack, the exploited machines send out too much traffic, distrusting the normal traffic flow, causing systems to fail.

Dedicated IP

An IP address that you don’t share with others.

When you use a VPN, you are most likely to use a shared IP address, for maximum anonymity.

However, some VPNs also have dedicated IP addresses that still hide your real IP addresses and can come in handy if you want to avoid getting blacklisted, or for working faster and easier.


DNS stands for Domain Name System, and it’s like the yellow pages of the internet.

When you want to access a website you type in a domain name in the browser.

On the other hand, your browser interacts through IP addresses. So, the DNS connects these two dots, by translating domain names to IP addresses.

DNS Leak

A VPN’s job is to hide your online activity from third parties, including your DNS queries.

When it fails to do this it means you are experiencing a DNS leak, and your ISP or other unauthorized entities can see which websites you visit or the apps you use, despite being connected to a VPN.

To check for a DNS leak you can use a DNS leak test tool, which is easy to find with a simple online search.

Domain Name

A domain name is your website’s name or the shortcut you use to get to the wanted destination on the internet (website).

If domain names did not exist, the only way to reach a website would be through typing the correct, and unique, website IP address.

For example, vpnAlert’s domain name is vpnalert.com, while the IP address is (just an example).


DPI stands for Deep Packet Inspection, and in this case, it refers to the advanced government system that can monitor and analyze your internet traffic.

Governments use this intrusive method to spy on their citizens and censor content.

More advanced VPNs that have obfuscation tools can help you avoid DPI.


Encryption is an incredibly complex process of encoding data.

But, in simple words, it means making data unrecognizable to third parties.

VPNs do it by using ciphers.

The most typical encryption in VPNs is the AES-256-bit encryption.


FVEY short for Five Eyes is a global surveillance alliance between the UK, the USA, Australia, New Zealand, and Canada.

Apart from FVEY, there is also the Nine-Eyes (the FVEY + Denmark, France, the Netherlands, and Norway), and 14-Eyes (the Nine Eyes + Belgium, Germany, Italy, Spain, and Sweden).

These controversial alliances gather intelligence on a global scale.


Geo-blocking is not to be confused with censorship, although it works similarly.

Usually, companies and organizations geo-block content, and they enforce it through software that recognizes, then blocks IP addresses, based on the location.

In other words, when content is geo-blocked, it’s unavailable for a certain demographic.

The reasons behind it can be many, but usually, it’s because of issues with usage rights (media production companies, streaming services, etc.).

Great Firewall of China

China’s notorious censorship politics are possible because of the so-called Great Firewall of China.

It’s an advanced system that allows the government to block access to online content they deem hurtful for the country.

It’s also the number one enemy of prop-privacy VPNs in that country, and it limits the free flow of online information.


When you open a website, you’ll notice that the URL starts with either http:// or https://.

These are short for Hypertext Transfer Protocol and Hypertext Transfer Protocol Secure (which is a secure extension to HTTP).

The two protocols allow data to travel between your browser and the website you are trying to reach.

The HTTP is not secure, meaning what you do on that website is “visible” to others (like your ISP), while HTTPS is a more advanced and secure version that blocks others from seeing what you do once you open the website.

IP Address

Think of an IP address (Internet Protocol address) as your online ID card. It doesn’t tell your name, but it does reveal your location.

Your router is configured to assign an IP address, which you then use on all the devices that you connect to the internet through that router.

When you are connected to a VPN, your local IP address changes and you are assigned another one, usually in a completely different location.

IP Leak

When you are using a VPN, you are assigned to an IP address that is different than the one appointed to you by your ISP.

That way, no one can know your true location and you can remain anonymous online.

However, when an IP leak occurs, it means the VPN is not doing a good job in hiding your online identity and is, in fact, leaking your real IP address.


IPv4 stands for Internet Protocol version 4.

It’s the original IP address scheme or the default system for defining numerical IP addresses.

IPv4 addresses make up for more than 90% of all the internet traffic flow, and they usually look something like this:


IPv6 stands for Internet Protocol version 6 – the next generation of IP address standards.

Since there are barely any IPv4 web-addresses left, IPv6 was created to expand the maximum available web addresses and it did.

Since it’s 128-bit (unlike the IPv4 which was 32-bit), it expanded the available web addresses to 2^128.


ISP stands for an Internet Service provider, and that’s basically your local network provider or the company that provides you with your internet connection.


You’ll find the kill switch as a security feature in most VPNs.

It’s a safety feature that protects you when your VPN crashes unexpectedly.


L2TP/IPSec is one of the security protocols you are most likely to run into when you are using a VPN.

The L2TP stands for Layer 2 Tunneling Protocol, which on itself does not provide any encryption.

The IPSec stands for Internet Protocol Security.

Together they make for a simple, yet secure VPN protocol.

The L2TP/IPSec can be a great choice if you want faster speed.

However, for maximum security opt for the OpenVPN instead.


Your VPN might keep some data on you. This information is often referred to as logs.

It can be either in the form of connection logs, like your email address, username, and password, how often you connect on a VPN server, etc.

Connection logs are kept so that the provider can ensure better functionality.

Usage logs, however, are information about your VPN usage like timestamps, the IP address you are using, etc. VPNs that keep most of this data are not trustworthy.


The dark web can be accessed through a different browser, called the Tor browser.

But unlike mainstream browsers like Chrome or Firefox that support most domain suffixes, Tor only works with domains that end in .onion.

This “onion” domain is specific for the dark web.


OpenVPN is currently the most used security protocol in VPNs, that enables a secure connection (secure tunnel) between the user and the VPN server.

The open-source software, combined with strong encryption, is the key player in VPN technology that keeps you safe on the internet.

P2P Software

P2P stands for peer to peer.

This software allows you to share files on the internet.

The “peers” are individual systems that can connect to each other online and share content, usually music, movies, or other software.

The most popular P2P software is BitTorrent.

VPNs that allow P2P sharing, actually allow using this software on their servers.

Ping Time

When we are measuring VPN server speeds, we always include the ping time.

It’s the time you need to get a response after you sent out a message.

In other words, the time it takes to send a small amount of data to the server, and get it back on your device again.

Good ping time is usually under 20s.


The PPTP is an outdated security protocol that some VPNs still use to this day. It’s short for Point-to-Point Tunneling Protocol, and it was once the standard in VPN technology.

Nowadays, PPTP falls behind some of the other available options, like OpenVPN and L2TP/IPSec because it’s not nearly as secure as these are.

Still, it does have its good sides, especially when it comes to speed, which is probably the reason why some VPNs still offer it as an option to their users.


Proxy servers are a bridge between you and the online world, similar to VPNs in some ways.

Just like a VPN, they connect you to the internet through an intermediary server, but they don’t offer the VPN’s security.

You can use a proxy server to hide your IP address, and they can be quite handy when you are using public Wi-Fi.

Still, it won’t encrypt your data, thus leaving you vulnerable to online threats.


RSA is an algorithm used to encrypt and decrypt data.

The name comes from the inventors – Ron Rivest, Adi Shamir, and Leonard Adleman.

Unlike AES encryption, which is symmetrical, RSA is asymmetrical and uses two different keys – a public one for encryption, and a private key for decryption.

The RSA-1024 encryption was allegedly hacked by the NSA a decade ago, but the RSA-2048 is quite secure, and it’s used by many VPNs. 

here is also the RSA-3072 or the RSA-4096 encryption.

These two are even stronger.


Smart DNS is a technology that works similar to proxies, in the way that it redirects your traffic.

It uses your DNS to access geo-blocked content on the internet.

But, unlike proxies that mask IP addresses, SmartDNS works by masking and redirecting only your DNS queries.


SSL and TLS stand for Secure Socket Layer and Transport Layer Security.

These are two commonly used encryption protocols, best known for securing HTTPS websites.

They are designed to enable secure communication over a computer network and are used in VPNs to enable a secure connection between the VPN client and the VPN server.

Tor (Tor Browser)

Tor is the browser you use to access the dark web.


Voice over IP or VoIP is the technology used in major apps nowadays that enables you to transmit voice and multimedia content over the internet.

For example, Skype, Viber, Telegram, etc.

VPN Client

To make VPNs user-friendly, VPN service companies developed native apps that you can use on most devices. These apps or software is called a VPN client.

Instead of manually setting up a VPN, you can download and set up the VPN client on your device.

Here, you will find everything that you need in one place, usually making it much easier to navigate the VPN.

VPN Protocol

All VPN service providers use VPN security protocols to offer maximum protection, combined with the right encryption.

The most common one nowadays is the OpenVPN protocol.

It’s also the most secure one.

Other VPN protocols commonly used are PPTP, L2TP/IPSec, SSTP, and IKEv2.

VPN Server

It’s a combination of VPN software and hardware.

On the VPN client, you choose a VPN server, which is a physical server that will redirect your traffic to the wanted destination.

At the same time, with the help of security protocols and encryption, the VPN server will keep your activity incomprehensible for anyone who might intersect it.

The server, based on its location, also provides you with a different IP address, which is why you can access geo-blocked content no matter where you are.

💥 Exclusive May Discounts 💥
Surfshark logo
PrivateVPN logo
NordVPN deal
Our partner, NordVPN, offers an exclusive discount for a limited time! Don't miss out on the chance to save extra money.
Or Try NordVPN for FREE