Nowadays, VPNs have become an essential part of our lives for both organizational and personal use. As of 2023, the virtual private network market size has grown to 44.6 billion dollars internationally. VPNs are widely utilized for various reasons, such as bypassing censorship, bypassing geo-blocks to access certain services, or enabling remote workers to access company networks over the Internet. VPNs connect users to private or public networks by creating secure tunnels while ensuring their privacy. In other words, data can be transferred securely over untrusted networks through encrypted connections with a VPN. But how does a VPN actually establish this connection? The answer is by VPN tunneling protocols.
Every VPN offers a unique set of tunneling protocols and standards. By changing the tunneling protocols, users can optimize VPN use for specific purposes. It should be noted that every tunneling protocol has its advantages and disadvantages. In this sense, we will expand on VPN tunneling protocols, how they ensure secure and fast connections and different tunneling protocol types.
VPN Protocol 101: What Is It and How Does It Work?
A VPN protocol is an asset that specifies all details about how to construct a VPN tunnel, and how to package and direct data over the created tunnel to a VPN server. In other words, a VPN protocol defines instructions for setting up a secure connection between the device and the server on VPN. Typically, VPN protocols control the encryption of tunnels and data packets before sending them and the specific methods used in transmissions. With encryption standards and transmission protocols, VPN protocols establish tunnels to securely exchange data over the Internet while protecting the connection against the threats lurking on it.
VPN protocols are tailored according to specific purposes and their performance differs naturally. Just by switching out the VPN protocol, users can immensely improve connection speeds three to four times faster. Encryption and security are also crucial besides the speed factor. If users want to prioritize secure connections, then the connection speed will be relatively slower. There are various VPN protocols to choose from. Since all VPN protocols have their unique strengths and weaknesses, users should pick according to their needs and purposes.
The Most Common VPN Protocols
1- L2TP
L2TP VPN protocol establishes VPN tunnels by fusing Layer 2 Forwarding into Point-to-Point Layering Protocol (PPTP). Because Layer 2 Tunneling Protocol doesn’t offer encryption, it is paired with IPSec to ensure the security of connections and data transfers. Once L2TP establishes the tunneling and confirms the authentication, the IPSec 256-bit AES variant encrypts the tunnel. That’s why, L2TP paired with IPsec is considered to be secure. Due to its double encapsulation and complex structure, it has slower connection speeds.
Also, Layer 2 Tunneling Protocol is highly compatible with all devices and operating systems. Therefore, it is great for organizations that want to enable remote connections to their business network. However, note that L2TP on its own lacks security and authentication. Additionally, bypassing geo-blocks and restrictions can be problematic with L2TP since it utilizes fixed ports. It also has firewall and instability issues.
2- OpenVPN
OpenVPN is an open-source tunneling protocol that utilizes OpenSSL cryptographic algorithms for private key exchange and establishes secure connections with transport layer security. It encrypts tunnels and connections with TLS/SSL key exchange. OpenVPN protocol manages the encryption methods and classifications of data packets being sent over established VPN tunnels. It offers high security and efficiency. Because it is an open-source VPN protocol, OpenVPN is constantly refined and any found bugs are patched by the open-source community. That’s why, high security can be maintained at all times and OpenVPN protocol protects the software and connections against emerging cybersecurity threats.
OpenVPN operates on the fourth level of the OSI model in UDP or TCP modes. While UDP mode doesn’t rely on the handshaking function, TCP relies on three-way handshaking. The similarity between these two modes is sending data packets in smaller clusters. Due to its complex database, OpenVPN consumes high bandwidth, so it has slower speeds during bandwidth-heavy activities. Also, OpenVPN is highly configurable and can operate on any port. By configuring it to run on port 443, OpenVPN can be used to bypass network limitations and firewalls. So, it can be used for accessing restricted or censored content.
3- WireGuard
WireGuard is the latest development in VPN tunneling protocols. It provides the fastest connection speeds among all tunneling protocols. Its speeds can reach 1000 Mbps, offering fast performance and bandwidth. WireGuard implements a simpler and significantly smaller codebase, which in turn results in improved maintenance and minimized attack surface. Also, WireGuard is structured with only 4000 lines of code — making it much easier to patch or troubleshoot. It establishes secure connections with cryptographic packages and symmetric encryption. Although it is in the development stage, it aims to solve the issues around the implementations of IPSec and OpenVPN.
Additionally, WireGuard is easy to implement, highly stable, and very agile tunneling protocol. Connections and reconnections are established in the blink of an eye with WireGuard even if the client’s IP address changes. WireGuard only utilizes public keys and the infrastructure doesn’t require certificates, therefore no need for certificate maintenance. UDP port 51820 is used in the default configurations of WireGuard but this specific port is prone to have security issues on public networks.
4- IKEv2
IKEv2 stands for Internet Key Exchange version 2 protocol developed by Microsoft and Cisco. IKEv2 is an encryption protocol for request and response actions. It utilizes Diffie-Hellman key exchange and X.509 public key infrastructure certificate for encryption and authentication procedures. Also, IKEv2 supports auto-connect and advanced cipher functions. Since it provides agility, speed, and low latency in connections, IKEv2 shows high performance in data transfer. Low latency is due to the reliance of IKEv2 on UDP ports. With its auto-connect functions, users can easily switch between cellular data and wifi without losing the session on smartphones. Even if the Internet connection is lost temporarily or IP is changed, it wouldn’t be an issue for the IKEv2 protocol since it immediately reconnects.
Although it offers great benefits, IKEv2 has problems regarding trustworthiness, firewall restrictions, configurations, and compatibility. IKEv2 is incompatible with devices and operating systems except for Windows, macOS, and iOS. So, all the other devices will require additional configurations. Since IKEv2 uses UDP port 500, this port can be restricted by administrators due to security reasons.
Final Remarks
VPNs have become essential tools in our daily lives for organizational or individual use. It is crucial to select the right one with proper VPN protocols to ensure secure connections and data privacy online. By simply switching the protocols, users can optimize VPN for specific purposes.
