What is a VPN and how to use private networks safely?

In an era of remote work and mobility, the boundaries of the corporate network have blurred irrevocably. Employees connect to critical company resources from home offices, hotel lobbies, coffee shops and airports, often using public, unsecured Wi-Fi networks. Such freedom, while convenient, poses a huge risk to data security. Every connection made over an open network is a potential opportunity for cybercriminals to eavesdrop on communications, steal passwords and infiltrate corporate infrastructure.

The answer to this fundamental challenge is a technology that has become an absolutely essential tool for any modern organization – VPN, or Virtual Private Network. It’s a technology that allows you to create a secure, encrypted “tunnel” across the public Internet, extending the boundaries of your corporate network all the way to your employee’s device, no matter where they are. In this guide, we’ll explain in simple terms what a VPN is, how it works, why it’s so important, and how to implement it in your company in an informed and secure manner.

What is a VPN (Virtual Private Network) and how does the tunneling technology work?

A VPN, or Virtual Private Network, is a technology that creates a secure and encrypted connection between a user’s device and a target network (such as a corporate network) over a public, untrusted network such as the Internet. It acts as a kind of “private corridor” inside the public highway. All Internet traffic generated by the device is first routed to the VPN server, and only from there to the destination. As a result, to an outside observer, all of the user’s activity looks like it’s coming from the VPN server, rather than the user’s real location.

At the heart of any VPN’s operation is tunneling and encryption technology. The process involves the data packets sent from the user’s device being “bundled” into additional packets (encapsulation), and then this entire “packet” is encrypted using strong cryptographic algorithms. The data thus secured is sent over the public Internet inside a secure, virtual “tunnel” to the VPN server. The VPN server, having the appropriate key, decrypts the data, “unpacks” the original packets and sends them to the destination network. The same process occurs in the other direction.

Thanks to this mechanism, even if someone (such as the administrator of a public Wi-Fi network or an ISP) intercepts our communications, they will only see a worthless, encrypted string of characters, impossible to read without a decryption key. Tunneling effectively hides both the content of our communications and their ultimate destination, ensuring the confidentiality and integrity of data sent over untrusted networks.

Why is a VPN an essential tool for any company that practices remote work?

In a remote working model, where employees perform their duties from different, often unsecured locations, a VPN ceases to be an option and becomes an absolutely essential component of a cyber security strategy. It provides two key pillars of security: secure access to internal resources and protection of corporate data in transit.

Remote workers need to access internal company resources, such as file servers, databases, CRM or ERP systems, which for security reasons are not and should not be exposed directly to the public Internet. A VPN acts as a secure, virtual “gateway” to the company’s network. Once a connection is established with the VPN server, the employee’s computer becomes a virtual member of the office’s local network, as if it were physically connected by cable. This allows access to all necessary resources in a controlled and secure manner, without having to open unsafe ports on the company firewall.

Moreover, remote work often involves the use of public, untrusted Wi-Fi networks – in cafes, hotels or airports. Such networks are ideal places for hackers to launch Man-in-the-Middle attacks, which involve eavesdropping and intercepting unencrypted communications. A VPN eliminates this risk. All of an employee’s Internet traffic, including login credentials, the content of emails and transferred files, is encapsulated in an encrypted tunnel. Even if an attacker intercepts this data, it will be useless to him. Implementing and enforcing a policy that every remote employee must be connected to the company’s VPN is the cornerstone of responsible security management today.

How does a VPN protect corporate data from eavesdropping on public Wi-Fi networks?

Public Wi-Fi networks, available in places such as coffee shops, hotels, airports and shopping malls, are extremely convenient, but they also pose a serious security risk. By their nature, they are open and untrusted networks, making them an ideal field for cybercriminals looking to intercept valuable data. A VPN is the most effective tool to protect against such threats.

The main risk in public Wi-Fi networks is Man-in-the-Middle (MitM) attacks. An attacker, located on the same network, can use simple tools to intercept all traffic flowing between the victim’s device and the Wi-Fi router. If the communication is not encrypted (e.g. when browsing on HTTP instead of HTTPS), the hacker can directly read its contents, including logins, passwords or credit card numbers. It can also create a fake, malicious access point (the so-called “Evil Twin”) with a name identical to a legitimate network (e.g. “Airport_WiFi”) to get victims to connect to it and thus take full control of their traffic.

A VPN completely neutralizes this threat. When a user activates a VPN connection, all of his Internet traffic is encapsulated in a heavily encrypted tunnel before it leaves the device. This means that even if an attacker intercepts our communications on a public Wi-Fi network, he will only see a stream of encrypted data that is useless to him. He won’t be able to read either the content of the information being sent, or even what sites or servers we are connecting to, because all communication is routed to the VPN server.

This allows an employee to work securely from anywhere, log in to company systems and transmit sensitive data, secure in the knowledge that their connection is fully protected from eavesdropping. Using a VPN on any public Wi-Fi network should be a habit for any informed user and a must for any employee with access to company data.

What are the differences between VPN protocols (e.g. OpenVPN, IKEv2) and which one is the most secure?

A VPN protocol is a set of rules and technologies that determine how a secure tunnel is established, how data is encrypted and how authentication is performed. There are several popular protocols, and choosing the right one has a key impact on the security, speed and stability of the connection. Among the most widely used are OpenVPN, IKEv2/IPsec and modern WireGuard.

OpenVPN has been the “gold standard” in the VPN world for many years. It is an open-source protocol, meaning that its code is publicly available and has been repeatedly reviewed by security experts for vulnerabilities. It is extremely flexible and configurable, and is considered very secure, using proven cryptographic libraries. Its main drawbacks are sometimes slightly slower speed compared to newer protocols and more complicated configuration from scratch.

IKEv2/IPsec (Internet Key Exchange v2) is a protocol jointly developed by Microsoft and Cisco, known for its exceptional stability and speed, especially when changing networks (such as switching from Wi-Fi to cellular data). It is natively supported in many operating systems (Windows, macOS, iOS), making it easy to configure. It is also considered very secure. It’s an excellent choice for mobile users who frequently change their Internet connection method.

The newest and increasingly popular player is WireGuard®. It is a state-of-the-art protocol designed from the ground up for simplicity, performance and superior security. It consists of far fewer lines of code than OpenVPN or IPsec, making it easier to audit and reducing the attack surface. It uses state-of-the-art cryptography and in tests shows much higher speeds and lower latency than older competitors. Because of these advantages, WireGuard is now considered by many experts to be the most secure and promising VPN protocol on the market.

Comparison of VPN Protocols

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What are the risks of using free and unreliable VPN services?

In search of savings, both individual users and small businesses often turn to free VPN services. However, it’s important to remember that nothing is free in the world of technology. Maintaining a global server infrastructure is extremely expensive, and if a provider doesn’t charge users, it has to make money in other ways. Unfortunately, most often the business model of free VPNs is to monetize their users’ data, which completely contradicts the idea of privacy and security.

The main threat is the collection and sale of user activity data. Many free VPN services explicitly claim in their terms and conditions to log sites visited, session duration and other metadata. This data is then anonymized (to varying degrees) and sold to data brokers, marketing and advertising companies. In extreme cases, unreliable providers may even sell data that directly identifies you. By using a free VPN, we often swap one “tracker” (our ISP) for another, much less reliable one.

Another serious risk is the injection of ads and malware. In order to generate revenue, providers of free VPNs can modify user traffic by injecting additional, often intrusive ads into the browsing experience. To make matters worse, there have been cases where free VPN apps are actually malware, designed to steal passwords, bank details or to include a user’s device in a botnet.

Finally, free VPN services often offer poor security. They may use outdated protocols, poor encryption, or suffer from leaks (such as DNS leaks) that cause some of our traffic to bypass the VPN tunnel anyway, revealing our true identity. Therefore, in business applications, the use of free VPNs is absolutely unacceptable and extremely irresponsible.

What are the key features of a good VPN for business (e.g., central management, kill switch)?

Choosing a VPN service for business purposes is governed by very different laws than choosing a solution for an individual user. Management, security and scalability features that allow a company to have full control over access to its resources become crucial.

The most important feature of the business-class solution is the central administration console. It allows the IT administrator to centrally manage all user accounts, grant and revoke permissions, as well as monitor activity and connection status in real time. It allows the creation of user groups with different levels of access (e.g., the finance department has access to accounting servers, while marketing does not), making it easier to implement the principle of least privilege. Integration with a company’s user directory (e.g. Active Directory/Entra ID) further automates the process.

Another key element is support for strong authentication and advanced security features. A business VPN must support multi-factor authentication (MFA), which adds another layer of protection beyond just passwords. An essential feature is also “Kill Switch,” a mechanism that automatically blocks all Internet traffic on the device if the connection to the VPN server is suddenly severed. This prevents accidental data leakage over an unsecured connection before the VPN tunnel is re-established.

Other important features include dedicated IP addresses for the company, which makes it easy to configure access rules, a strict “no-logs” policy (no user activity logs stored) on the provider’s side, and high performance and a global network of servers that provides a stable and fast connection for employees around the world. Also important is professional technical support (support) 24/7, which is able to help quickly in case of problems.

What is the process of implementing and configuring a corporate VPN server?

Deploying a corporate VPN server is a process that requires careful planning and technical expertise to ensure both the security and reliability of the solution. The process can be broken down into several key steps.

1. Planning and Solution Selection. The first step is to analyze business needs. It is necessary to determine how many employees will use the VPN at the same time, what applications and resources will be shared, and what the performance requirements are. Based on this, you should decide on the choice of technology: whether you will deploy a solution based on open-source software (e.g. OpenVPN, WireGuard) on your own server, whether you will use a ready-made solution built into your network devices (e.g. next-generation firewalls), or whether you will opt for a cloud VPN service from a specialized provider.

2 Infrastructure Preparation. Then you need to prepare the appropriate infrastructure. This can be a dedicated physical or virtual server (on-site or in the cloud), on which the VPN server software will be installed. This server must have adequate computing power, network bandwidth and must be properly secured (hardened operating system, regular updates). Appropriate rules must also be configured on the company’s firewall to allow incoming traffic on the ports used by the VPN protocol.

3 Installation and Setup. In this phase, the VPN server software is installed and configured. The key here is to properly configure security parameters: choosing strong protocol and encryption algorithms, generating certificates and keys, and configuring user authentication methods (e.g. integration with Active Directory, enabling MFA). It is also necessary to define pools of IP addresses that will be assigned to users when they connect, and configure routing rules that will determine which resources on the corporate network they will have access to.

4 Customer Distribution and Training. Once the server is up and running and tested, the VPN client software must be prepared and made available to employees, along with the relevant configuration files. This stage must be combined with training, during which you explain to employees how to install, configure and use the VPN client, and what security policies apply to them. It is also necessary to provide technical support during the initial period.

What security policies should apply to employees using VPNs?

Simply implementing VPN technology is only half the battle. To be fully effective, the solution must be supported by clear and rigorously enforced security policies that specify how employees are to use it. These policies should be part of the company’s overall security policy.

First and foremost, the policy should make it mandatory to use a VPN for any remote work. It should be made clear that any access to company resources or work with company data from outside the office must be done only through an active VPN connection. This is especially true if an employee uses public or untrusted Wi-Fi networks.

The policy must also define rules for authentication. It should require employees to use strong, unique passwords for their VPN accounts and, crucially, mandate the use of multi-factor authentication (MFA) when available. It should also prohibit employees from sharing their VPN credentials with anyone, including other employees.

It’s also a good idea to implement split tunneling in a controlled manner. The policy should specify whether all of an employee’s Internet traffic is to be routed through the company’s VPN (which is safer, but puts more strain on the connection), or whether traffic to company resources is allowed to go through the VPN, and traffic to the public Internet (e.g., streaming services) is allowed to go bypass the tunnel. This decision must be made consciously by the IT department. The policy should also serve as a reminder that even when connecting to a VPN, it is still incumbent on the employee to follow all other security rules, such as protection against phishing and malware.

Does a VPN guarantee 100% anonymity on the Internet?

No, and this is one of the most common misunderstandings about VPN technology. The main purpose of a VPN is the privacy and security of your connection, not the anonymity of your identity. While a VPN effectively hides our activity from the ISP and masks our true IP address from the sites we visit, it does not make us fully anonymous.

A key element is trust in the VPN service provider. Since all of our traffic goes through its servers, that provider technically has the ability to monitor and log our activity – it knows who we are (based on account and payment information) and what sites we visit. Reputable providers have a strict “no-logs” policy, meaning that they commit to not storing any data about user activity. However, with free or unreliable services, there is no such guarantee. In addition, the VPN provider, as a legal entity, may have to share data with law enforcement under a court order.

What’s more, a VPN does not protect against other tracking methods. If we log into our Google or Facebook account after connecting to a VPN, these services will easily identify us and link our activity to our profile. A VPN also doesn’t protect against tracking via cookies (if we don’t clear them regularly) or advanced browser fingerprinting techniques.

A technology designed for true anonymity is the TOR network, which operates on a completely different, decentralized basis. However, for the vast majority of users and business applications, the level of privacy offered by a trusted, paid VPN service is perfectly adequate. However, it is important to understand the difference and not confuse privacy with anonymity.

What are the most common configuration errors that weaken VPN security?

Even the best VPN technology can become useless if it is configured incorrectly. There are several common mistakes that can significantly weaken or completely undermine the security that a virtual private network is supposed to provide.

One of the most serious mistakes is using weak or outdated encryption protocols and algorithms. When configuring a VPN server, an administrator should choose modern and secure protocols such as WireGuard, OpenVPN or IKEv2, and avoid old and broken ones such as PPTP. Equally important is the use of strong encryption algorithms (such as AES-256) and hash functions. Leaving the defaults, which are often weak, is asking for trouble.

Another common problem is the improper configuration of “split tunneling” (split tunneling). This is a feature that allows some traffic to be routed through a VPN tunnel at the same time (e.g. to corporate resources), and some to be routed bypassed (e.g. to the public Internet). Misconfiguration of this feature can lead to a situation where sensitive corporate traffic accidentally “leaks” outside the encrypted tunnel, becoming visible to potential eavesdroppers.

Other common mistakes include failing to implement multi-factor authentication (MFA), making it sufficient to steal an employee’s password alone to gain access to the entire corporate network, and assigning overly broad privileges. An employee connected to a VPN should not have access to the entire corporate network by default. Use network segmentation and firewall rules to limit his access to only those servers and services that he absolutely needs to work. Regular auditing of VPN server configurations is key to maintaining a high level of security.

Does a VPN slow down internet speed and how can it be minimized?

Yes, using a VPN inherently involves a certain drop in the speed of your Internet connection. This is an unavoidable consequence of the two main processes that occur in the background: encryption and the additional path that data must travel. However, with modern protocols and good services, this drop is often small and almost imperceptible in everyday use.

The process of encrypting and decrypting data in real time requires some CPU processing power on the user’s device and on the VPN server. Although modern processors can handle this perfectly well, it is an additional burden that can affect speed. The main slowing factor, however, is the extra distance and additional “stop” along the data path. Instead of connecting directly to the destination site, our traffic must first reach the VPN server (which increases latency, known as ping), and only from there is it routed further.

There are several ways to minimize the negative impact of VPNs on speed. First, choosing the right protocol is key. Modern protocols, such as WireGuard or IKEv2, are much lighter and more efficient than the older OpenVPN, offering noticeably higher speeds.

Secondly, connect to a VPN server that is located as close to our physical location as possible. The shorter the distance your data has to travel to the server, the lower the latency will be. Reputable VPN providers offer hundreds of servers in different locations around the world, allowing you to choose the optimal one. Finally, make sure that our base Internet connection itself is fast enough. Even the best VPN won’t speed up a slow connection. In a corporate context, it’s crucial to ensure that the VPN server has enough Internet bandwidth to be able to handle traffic from all connected employees simultaneously.

How can nFlo’s network construction and security services help your company implement a reliable and secure VPN solution for your employees?

Implementing a corporate VPN solution is a task that requires not only knowledge of the technology itself, but also a deep understanding of secure network design, identity management and device configuration. At nFlo, we specialize in providing comprehensive services that cover the entire lifecycle of secure remote access – from analysis and design, to implementation, to maintenance and monitoring.

Our support begins with the consulting and design phase. We analyze your company’s specific needs, scale of operations and security requirements to help you choose the optimal VPN technology – whether it’s a solution based on a dedicated next-generation firewall or a dedicated VPN server. We design the architecture of the solution, taking into account best practices for network segmentation so that remote workers only have access to the resources they need.

Then, our team of experienced engineers carries out the implementation and configuration process. We install and configure the VPN server, paying special attention to security aspects: we implement the latest, most secure protocols, configure strong encryption and, crucially, integrate the solution with existing authentication systems, such as Active Directory, and implement multi-factor authentication (MFA). We make sure that the solution is not only secure, but also efficient and reliable.

Our services also include the preparation of security policies and employee training to ensure that the tool is used in an informed and secure manner. We also offer ongoing management and monitoring services for your VPN infrastructure, making sure it is regularly updated and responding to any incidents. When you choose nFlo, you get a partner who will not only provide you with the technology, but provide comprehensive care for one of the most important elements of your company’s security strategy – secure remote access.