What is a VPN tunnel and how does it work? Everything you need to know

With a VPN tunnel, VPN software creates an encrypted connection, allowing you to browse the internet securely without revealing personal details like your IP address.

Learning about tunneling can aid in selecting the most secure option. This article delves into the functionality of a VPN tunnel and the features offered by top VPN providers.

What is a VPN tunnel?

A VPN tunnel establishes a secure link between your device, like a computer or smartphone, and a VPN server. All data transmitted through this connection is encrypted.

Tunneling allows you to transmit data to a VPN server via the public internet without exposing it to unauthorized access. Your data remains shielded from potential threats such as hackers, government surveillance, and your internet service provider. Even if someone intercepts your connection and attempts to access your data, it remains encrypted and unreadable.

Once the encrypted data reaches the VPN server, it can be decrypted and forwarded to a website or online service. Similarly, data returned to your device, such as website information, is encrypted as it travels back through the VPN tunnel.

How does VPN tunneling work?

VPN tunneling comprises four essential stages, as delineated beneath.

1. Activation

To initiate a VPN tunnel, activate your VPN and select a server for connection.

2. Connection

Your VPN software establishes a secure link to the designated server through the VPN tunnel. All internet traffic to and from your device is routed through this tunnel.

3. Encryption

Before exiting your device and entering the VPN tunnel, all outgoing data undergoes encryption. This ensures that data passing through the tunnel remains indecipherable without the encryption key provided by the VPN software.

4. Decryption

Upon reaching the VPN server, data is decrypted using the encryption key specific to your VPN software. Subsequently, the data is transmitted to the desired website or destination.

This process is reversed when data is sent from a website to your device – encryption takes place on the VPN server, and your VPN software decrypts the data upon arrival on your device.

Types of VPN tunnel protocols

Various protocols, referred to as methods, are utilized by VPNs to create a tunnel.

Diverse VPN tunnel protocols employ distinct encryption techniques, affecting the privacy and security of your connection.

Below, we'll explore 5 prevalent VPN tunnel protocols.

OpenVPN

OpenVPN stands as the most prevalent VPN tunneling protocol, renowned for its robust security and swift connections.

Pros

• Flexible data encryption options - While many VPNs employ 256-bit Secure Sockets Layer (SSL) encryption with the OpenVPN protocol, some opt for more fortified encryption methods like Blowfish or Advanced Encryption Standard (AES).
• Unique encryption key per VPN session - In the event of a potential breach where the encryption key is compromised, initiating a new VPN session promptly re-secures your data with a fresh encryption key.

Cons

• Slower compared to WireGuard - Historically, OpenVPN was esteemed as the fastest VPN tunneling protocol. However, the advent of the WireGuard protocol has introduced faster connection speeds.

WireGuard

WireGuard emerges as a comparatively recent VPN protocol, developed in 2020, and is lauded for its superior speed and security compared to OpenVPN. With more VPN platforms integrating support for WireGuard tunneling, it is poised to become the predominant protocol in the future.

Pros

• Frequent generation of new and distinct encryption keys - Security for your connection is routinely refreshed without necessitating the initiation of a new VPN session.
• Minimalistic codebase - WireGuard's protocol is crafted with a mere 4,000 lines of code, contrasting with OpenVPN's extensive 70,000 lines of code. This streamlined codebase facilitates easier auditing, reducing the likelihood of unidentified vulnerabilities that could be exploited.

Cons

• Static IP address - Unlike OpenVPN, WireGuard does not automatically alter your IP address with each new connection. Consequently, this static IP address feature may render it easier for potential attackers to pinpoint your location, even if they cannot access your data.

IKEv2/IPsec

IKEv2/IPsec merges the Internet Key Exchange version 2 (IKEv2) protocol for encryption key management with the Internet Protocol Security (IPsec) tunneling protocol.

Pros

• Tailored for mobile devices - IKEv2/IPsec automatically re-establishes a tunnel in case of connection loss, making it particularly advantageous for mobile devices prone to network changes.
• Swift connection speeds - While not as rapid as WireGuard, IKEv2/IPsec generally delivers comparable connection speeds akin to those achieved with OpenVPN.

Cons

• Limited compatibility - While native support for IKEv2/IPsec is available on newer versions of Windows and macOS, it may necessitate configuration adjustments to function on other operating systems.

L2TP/IPsec

L2TP/IPsec integrates the Layer 2 Tunneling Protocol (L2TP) with IPsec. However, it's widely regarded as insecure, leading many VPN providers to discontinue its support.

Pros

• Seamless compatibility - L2TP/IPsec functions seamlessly on most operating systems, facilitating its use across diverse devices.

Cons

• Potential security vulnerabilities - There have been indications that the National Security Agency has identified vulnerabilities in VPNs, including breaching LT2P connections, raising concerns about data security.
• Sluggish performance - L2TP/IPsec connections typically exhibit slower speeds compared to protocols like OpenVPN, WireGuard, or IKEv2/IPsec.

Secure Socket Tunneling Protocol (SSTP)

Secure Socket Tunneling Protocol (SSTP) is a secure and moderately fast VPN protocol originated by Microsoft.

Pros

• Effective in bypassing firewalls - SSTP is adept at circumventing firewalls, making it particularly suitable for accessing geographically restricted websites.

Cons

• Limited compatibility - SSTP is tailored primarily for Windows and Linux environments, rendering it incompatible with other operating systems.
• Closed-source nature - The protocol's underlying code remains proprietary, lacking transparency for security analysts to scrutinize potential vulnerabilities.

Point-to-Point Tunneling Protocol (PPTP)

Point-to-Point Tunneling Protocol (PPTP) is a VPN protocol introduced by Microsoft in the 1990s. Its usage has declined over time due to security vulnerabilities and performance issues.

Pros

• Compatibility with legacy systems - PPTP remains compatible with older Windows versions like Windows 95 and Windows 98.

Cons

• Security risks - PPTP employs encryption methods that are considered weaker compared to contemporary standards, posing security vulnerabilities.
• Performance limitations - PPTP tends to offer limited bandwidth and slower encryption/decryption processes, impacting connection speeds unfavorably when compared to other tunneling protocols.

Split tunneling

Split tunneling is a feature that enables users to specify which internet traffic is routed through their VPN tunnel and which traffic accesses public networks directly. This functionality proves beneficial when users wish to, for instance, access geo-blocked streaming content from another country while simultaneously browsing local websites. By configuring split tunneling, users can direct traffic from specific applications, like streaming services, through the VPN tunnel while allowing other traffic, such as browser activity, to bypass the VPN and use the local network.

VPN kill switches

VPN kill switches serve as vital security features in case of unexpected VPN connection interruptions, which could occur due to various reasons like software crashes or brief WiFi signal losses. In such instances, devices might revert to transmitting data over public internet connections, potentially exposing users' IP addresses. To prevent this, a VPN kill switch automatically terminates internet connections if the VPN tunnel is compromised. This ensures continuous protection of your IP address even during VPN disruptions, making it an indispensable tool for maintaining online privacy.

What tunneling protocols are provided by well-known VPN services?

Every VPN employs tunneling to create a secure connection between your device and the internet. However, the range of tunneling protocols available may vary among VPN providers.

The following table outlines the protocols supported by various well-known VPN services.

Final thoughts on VPN tunneling

A VPN tunnel is crucial for establishing a secure link between your device and a VPN server, ensuring encrypted data transmission. While all VPN software employs a VPN tunnel to safeguard web traffic, the level of security and connection speed can vary across different protocols. For guidance on selecting the most secure VPN app tailored to your requirements, refer to our comprehensive guide.