VPN is a technology that enables a secure connection over an insecure network (such as the internet). To achieve this, VPNs encrypt the user’s data and route it through a secure tunnel: This way, no one from outside can access or manipulate this information.
The function of a VPN in networks
Virtual Private Networks protect internet traffic. When someone connects to a VPN server, their entire data traffic is routed through an encrypted tunnel to the server. From there, it reaches the open internet, but under the IP address of the server. To observers, it appears as if the data traffic is coming from the server and not from the user’s device. Since they are encrypted, the data cannot be read by anyone, not even by the internet service provider.
Advantages and areas of application
- Secure remote access: Employees can securely access company networks, even when working mobile or from home office.
- Data protection: Users’ privacy is protected through encryption and anonymization, keeping their activities hidden from hackers, for example.
- Bypassing geo-restrictions: VPNs are often used to access geographically restricted content such as that of streaming services or websites blocked in certain countries.
- File sharing: The secure transfer of files between teams or within organizations is facilitated by using a Virtual Private Network.
VPN connection and data transfer
A VPN establishes a secure connection over an insecure network. To do this, the user installs software on their device. This then acts as a client. The client sends a request to a VPN server, which verifies the user’s login information. Once this is done, an encrypted connection (a VPN tunnel) is established. All data that subsequently flows through this tunnel is encrypted and not visible to outsiders.
A VPN tunnel works like a protective shield around user data. It uses encryption protocols such as IPsec or OpenVPN to create a private communication channel. The data is encrypted before it leaves the user’s device and is only decrypted at the VPN server.
Different types
- Site-to-Site VPN: Connects two networks together so that they act as a single network. This type of VPN is often used by companies to securely connect offices in different regions.
- End-to-Site VPN: Allows individual users to connect from their device to a network (e.g., the company network). Ideal for remote workers to gain access to internal resources.
- End-to-End VPN: Protects the transmission of data between two end devices. This is often used for secure communications, such as confidential chats or phone calls.
Example: Two branches of a company, one in Berlin and the other in Munich, use a site-to-site VPN to securely exchange data. For employees, it seems as if the resources of the other location are locally available.
Authentication mechanisms and access controls
In addition to encryption, authentication mechanisms and access controls are crucial for the security of the Virtual Private Network. These mechanisms ensure that only authorized users gain access. Authentication can occur through various methods:
Passwords: Simple, but often insecure.
Two-factor authentication (2FA): This introduces an additional layer of security. The method combines something the user knows (for example, a password they’ve set) with something they possess (for example, a digital device they own).
Digital certificates: A more secure solution where VPN client and server use certificates for mutual authentication.
Security risks and remedies
Although VPNs have strong encryption and require authentication, they are not without security risks. Common threats include:
Man-in-the-Middle attacks (MITM): An attacker intercepts data between the VPN connection. Solution: Only use trusted networks.
Software vulnerabilities: Users should promptly perform updates of their software and operating system to close security gaps.
DNS leaks: DNS requests can be sent outside the VPN tunnel. Solution: Correctly configure VPN client to avoid DNS leaks.
The security of Virtual Private Networks can be significantly enhanced by choosing strong encryption protocols, implementing multi-factor authentication, and being aware of potential risks.
