What is a VPN Tunnel & How VPN Tunneling Works?

Ivan Stevanovic

Updated: July 14, 2023

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As we browse the internet, we leave crumbs of browsing data on the pages we visit. Here’s where the VPN tunnel enters the frame. It provides an encrypted link, or a tunnel, between our personal device and the external network.

Our data can be both valuable and dangerous if it falls into the wrong hands. A virtual private network encrypts and hides your browsing behavior from prying eyes. It also gives you access to specific censored and geographically blocked sites while it hides your data. All of this depends on reliable virtual private network tunnels.

Having a secure tunnel for a VPN is a must, as it encrypts your IP address and any browsing-generated data, keeping it safe from prying government agencies, hackers, and even your internet provider.

The Essence of VPN Tunneling

To successfully encrypt and hide your data, you’ll have to use a VPN app that comes with a tunneling protocol. It’s easy to use; you simply log in and activate the VPN before you start browsing. When you visit pages, your internet service provider – and by extension any other party that might be spying on you – will not be able to see your IP address. Instead, it’ll show the VPN’s IP address.

This VPN tunnel service will protect your privacy on the internet. Such programs are desinged to prevent leaking, which is when your actual IP address gets revealed while you’re using a VPN.

But tunnels are only as secure as their building blocks. The encryption methods that tunneling protocols use need to be strong enough to prevent data loss and stop ISPs or government agencies from gaining access to your information.

How VPN Tunneling Works

Every safe VPN connection depends on four crucial factors: tunneling, encryption, key exchange, and the kill switch.

• Tunneling: As soon as your computer commences the VPN connection, the data goes through the VPN tunnel software in the form of packets. Every packet includes a piece of data that the others cannot see. When it reaches its final destination, the container is removed, and the data becomes accessible again. Data packaging works in both directions.
• Encryption: The data that goes through the tunnel of the VPN connection is modified into an inaccessible form known as the “ciphertext.”
• Key exchange: Keys are a string of numbers that both the server and the VPN client use to decrypt the data packets.
• Kill switch: All well-known VPNs have a built-in automatic kill switch function that stops your internet traffic from going through the VPN tunnel immediately in case of a failed connection with a VPN server. This prevents your IP address from leaking and getting revealed to third parties.

Certain VPNs like NordVPN offer an option for split tunneling. With this option, you manually select which websites and apps have to go through a VPN. That means that if you want to watch the latest movies from streaming sites, you’d add those sites to your VPN list, while you might decide to access your email inbox without using the VPN.

The Variety of Tunneling Protocols

A particular type of VPN tunnel might grant better protection than others thanks to the tunneling protocol it uses. These protocols age and become easier to crack over time due to the strength of their encryption. For that reason, there are several tunneling protocols in use today.

PPTP

Point to Point Tunneling Protocol (PPTP) is the oldest tunneling protocol that’s still actively used today. Believe it ir not, Microsoft actually developed PPTP for Windows 95. It’s exceedingly fast at connecting thanks to the low strength of its encryption. This tunneling protocol only requires a username, a password, and a server address.

The downside of using this VPN tunnel configuration protocol is that it has become simple for hackers to breach due to its paltry encryption. As a result, the PPTP gives you fast connection speeds but sacrifices the security of your IP address and browsing data in the process. Indeed, a number of security vulnerabilities were discovered way back in 1998, so government agencies can now crack this protocol easily.

L2TP/IPSec

Layer 2 Tunneling Protocol (L2TP) and Internet Protocol Security (IPSec) is a more secure tunneling protocol than the simplistic PPTP. Thanks to its double layer of protection, L2TP/IPSec provides two encryptions to protect users’ online data.

This tunneling protocol uses AES-256 bit VPN tunnel encryption, which is the most sophisticated encryption standard available today. However, since L2TP/IPSec uses double encryption, its connection speeds are sluggish compared to PPTP. Another issue is that it uses fixed ports, which allows some firewalls use to block its VPN connections.

SSTP

Secure Socket Tunneling Protocol (SSTP) can be implemented only on Windows operating systems. Online data moves through the tunnel with the help of the secure socket layer technology that’s native to Windows. SSTP provides strong encryption and doesn’t use fixed ports, which makes it great for bypassing firewalls.

A VPN tunnel with the SSTP protocol gives you a secure connection thanks to Transport Layer Security (TLS) within your browser. You can quickly see if TLS is active by checking that the site address begins with “https.” The main drawback is that only Windows users can rely on the SSTP protocol; it’s not available on other systems. SSTP hasn’t been analyzed for possible backdoors, which is another minus.

Open VPN

One of the most robust protocols available nowadays is Open VPN, which uses AES-256 encryption. It’s one of the newer tunneling protocols and it uses open-source code for its VPN, meaning that experts regularly fix possible security flaws, since the programming code is openly available to be improved.

Open VPN is VPN tunnel software that works with all notable operating systems, including Windows, Mac, Linux, Android, and iOS. The protocol even works on FreeBSD, Open BSD, NetBSD, and Solaris operating systems.

Open VPN is packed with powerful cryptographic algorithms that provide very secure encryption and fast speeds while bypassing firewalls.

IKEv2

The IETF defined the first version of the Internet Exchange Protocol in November 1998. IKEv2, the second version – which remains widely used today – was published in December 2005. The protocol creates identical symmetric encryption keys for both the VPN server and the VPN client. The same key encrypts and decrypts the data that flows through the VPN tunnel.

The setup is more complex than PPTP, but the IKEv2 protocol can easily bypass firewalls at similarly rapid connection speeds to what PPTP provides. It uses 256-bit encryption in several ciphers, like AES, 3DES, Camellia, and ChaCha20. IKEv2 also employs the PFS + protocol, which allows uninterrupted connection when switching networks.

WireGuard

The WireGuard protocol is the most recent of the entire bunch, having originally been implemented on Linux systems in 2020. Thanks to its open-source code, WireGuard was released on other popular operating systems in 2021.

When setting up a VPN tunnel, the WireGuard protocol applies cryptographic primitives that users cannot modify. In case they find a severe security flaw, members of the VPN community release a new patched version. This protocol also uses key-impersonation security, replay and denial-of-service attack protection, and post-quantum cryptographic resistance.

WireGuard is very easy to use thanks to its simplicity and regularly outperforms the Open VPN protocol on Linux systems. The only drawback is that connection speeds are not that fast on other operating systems.

Securing Your Online Identity

No matter which tunneling protocol you choose, you’ll have better protection against online ID theft if you use a VPN. The L2TP/IPSec VPN tunnel offers strong encryption at slower connection speeds, while SSTP uses similarly secure encryption, but only for Windows systems. Open VPN offers powerful encryption and the ability to bypass firewalls, while its improved version – WireGuard – provides better speeds on Linux than on other operating systems. IKEv2 is protection-oriented but more complex to use, while PPTP is obsolete.