IKEv2 vs. OpenVPN: What’s the Difference?

Last updated on February 21, 2025

The main difference between IKEv2 and OpenVPN is that IKEv2 is a standard protocol that is natively supported by many operating systems and offers faster and more stable connections, while OpenVPN is an open-source protocol that requires third-party software and offers more flexibility and security options.

If you are looking for a secure and reliable VPN protocol, you may have come across IKEv2 and OpenVPN. These are two of the most popular and widely used protocols in the VPN industry, but what are the differences between them, and which one should you choose? In this article, we will explain what IKEv2 and OpenVPN are, how they work, and what are their advantages and disadvantages. We will also provide some tips on how to use them effectively.

What are IKEv2 and OpenVPN?

IKEv2 and OpenVPN are both VPN protocols that create a secure tunnel for communication between a VPN client and a VPN server. They use encryption and authentication to protect the data that travels through the tunnel from being intercepted or tampered with by third parties.

However, they differ in their design, implementation, features, and performance. Let’s take a closer look at each protocol.

What is IKEv2?

IKEv2 stands for Internet Key Exchange version 2. It is a standard protocol described in RFC-7296 that was jointly developed by Microsoft and Cisco. It is a successor to IKEv1, which was defined in RFC-2409.

IKEv2 is a tunneling protocol within the IPSec protocol suite. It is responsible for setting up Security Associations (SAs) for secure communication between VPN clients and VPN servers within IPSec. SAs are agreements on how the security and authentication of the tunnel will take place.

IKEv2 uses UDP as the transport layer protocol, usually on port 500. It uses Diffie-Hellman (DH) or Elliptic Curve Diffie-Hellman (ECDH) for key exchange, which is a process of generating a shared secret key that can be used to encrypt and decrypt the data. It can use a big number of cryptographic algorithms, such as AES, Blowfish, and 3DES, for encryption.

IKEv2 is often paired with IPSec, which is another protocol that provides additional security features, such as Encapsulating Security Payload (ESP) or Authentication Header (AH). The combination of IKEv2 and IPSec is commonly known as IKEv2/IPSec.

What is OpenVPN?

OpenVPN is an open-source protocol that was created by James Yonan in 2001. It is not based on any standards, but it uses the OpenSSL library extensively to provide encryption and authentication. It also uses the TLS protocol for key exchange.

OpenVPN can use UDP or TCP as the transport layer protocol, depending on the configuration. It can also use any port number, but it usually uses port 1194 for UDP and port 443 for TCP. Port 443 is the same port used by HTTPS traffic, which makes it harder to block or detect by firewalls.

OpenVPN can also use a large number of cryptographic algorithms, such as AES, RC5, Blowfish, ChaCha20, and 3DES, for encryption. It supports Perfect Forward Secrecy (PFS), which means that it generates a new encryption key for each session, making it more resistant to attacks.

OpenVPN is not natively supported by any operating system, but it is available on many platforms through third-party software. Some of the most popular software includes the official OpenVPN client, Tunnelblick for macOS, OpenVPN Connect for iOS and Android, and OpenVPN GUI for Windows.

IKEv2 vs. OpenVPN: What are the Similarities Between IKEv2 and OpenVPN?

Before we delve into how OpenVPN and IKEv2 differ, let’s take a look at what they have in common.

• Both IKEv2 and OpenVPN provide full confidentiality, authentication, and integrity. This means that they prevent anyone from reading, modifying, or spoofing the data that travels through the tunnel.
• Both IKEv2 and OpenVPN support Perfect Forward Secrecy (PFS). This means that they generate a new encryption key for each session or connection, making it harder for attackers to decrypt past or future traffic even if they obtain one key.
• Both IKEv2 and OpenVPN have no proven major vulnerabilities and are generally considered to be secure. They are constantly updated and audited by their developers and communities.

IKEv2 vs. OpenVPN: What’s the Difference Between IKEv2 and OpenVPN?

Here’s a table describing the differences between IKEv2 vs. OpenVPN.

Note that just like L2TP, IKEv2 is often paired with IPSec, so some of the differences include the differences between OpenVPN and IKEv2/IPSec.

IKEv2	OpenVPN
IKEv2 is short for Internet Key Exchange version 2.	OpenVPN is sometimes shortened to OVPN. VPN stands for Virtual Private Network.
IKEv2 is a standard described in RFC-7296. Open-source implementations exist (e.g., OpenIKEv2).	OpenVPN is an open-source protocol and is not based on standards.
IKEv2 uses UDP as the transport layer protocol, usually on port 500.	OpenVPN can use UDP or TCP as the transport layer protocol, on any port number.
IKEv2 uses Diffie-Hellman (DH) or Elliptic Curve Diffie-Hellman (ECDH) for key exchange.	OpenVPN uses SSL/TLS for key exchange.
OpenVPN can use a large number of cryptographic algorithms for encryption, such as AES, RC5, Blowfish, ChaCha20, and 3DES.	OpenVPN can use a big number of cryptographic algorithms for encryption, such as AES, RC5, Blowfish, ChaCha20, and 3DES.
IKEv2 is natively supported by Windows 7 and higher, macOS 10.11 and higher, and most mobile operating systems, including BlackBerry.	OpenVPN is not natively supported by any system but is available on Windows XP and later, Solaris, macOS, Linux, iOS, Android, and other desktop and mobile operating systems through third-party software.
In most use cases, IKEv2 does not require any additional software.	OpenVPN relies on third-party software.
IKEv2 is a very fast protocol.	OpenVPN is fast, but usually not as fast as IKEv2.
IKEv2 uses UDP port 500, which makes it easy to block for network admins.	OpenVPN can use TCP port 443, which is the same port used by HTTPS traffic. Blocking it without blocking other HTTPS traffic might be hard.
IKEv2 employs the MOBIKE protocol to let mobile Virtual Private Network (VPN) clients keep the connection while moving from one address to another.	OpenVPN comes with the –float command that accepts authenticated packets from any address. However, OpenVPN is more cumbersome than IKEv2 in this aspect.

Choosing the Right VPN Protocol for Your Needs

Selecting between IKEv2 and OpenVPN depends on various factors, including your specific requirements and environment. Here’s how to determine which protocol suits your needs:

• Assess Your Network Environment: If you frequently switch between networks or rely heavily on mobile data, IKEv2 offers superior stability and faster reconnections.
• Evaluate Security Requirements: For scenarios demanding high configurability and robust security features, OpenVPN provides extensive options and flexibility. For enhanced security, integrating multi-factor authentication (MFA) is essential. Explore Rublon’s options for MFA for OpenVPN to add an extra layer of protection to your remote access.
• Consider Compatibility: Ensure that the chosen protocol aligns with your devices and operating systems. IKEv2 is natively supported on many platforms, while OpenVPN requires third-party applications but offers broader compatibility.

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Conclusion of IKEv2 vs. OpenVPN

IKEv2 and OpenVPN are two secure protocols used to establish and authenticate communication between a VPN client and a VPN server. Generally, IKEv2 is faster than OpenVPN. Further, IKEv2 has the ability to re-establish a connection after a loss of signal and handle changes in the network very well thanks to the MOBIKE protocol. On the other hand, OpenVPN can use both UDP and TCP as transport layer protocols. It is open-source, secure, reliable, and cost-efficient. 

Summing up, if you need a secure and versatile protocol, OpenVPN is a good choice. However, if you care about speed or want to use a mobile VPN client, go for IKEv2.