What is IKEv2?

What is IKEv2? (Guide for 2024)

Published on: March 19, 2023
Last Updated: March 19, 2023

What is IKEv2? (Guide for 2024)

Published on: March 19, 2023
Last Updated: March 19, 2023


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What is IKEv2?

A VPN protocol is known as the method by which a virtual private network (VPN) secures the link between your computer and the VPN’s server.

To accomplish this, the targeted computer and then the VPN server’s validity must be validated, and then an access code must be generated. Both of them can utilize that.

The data can be encrypted with this technology, delivered securely between the computer and the server, and then decoded again when it arrives.

It doesn’t matter how reliable a VPN service provider is; if it doesn’t use a robust protocol, it can’t truly protect its users’ data.

IKEv2 is a crucial protocol, and a virtual private network (VPN) cannot function properly without it.

Throughout the past few years, the IKEv2 VPN protocol has steadily amassed a growing number of followers, particularly among mobile users.

Given how effective and safe the treatment is, it is not difficult to understand why this is the case.

But to be more specific, what exactly is IKEv2?

How exactly does it ensure that those who use the internet have a secure experience?

So, in that case, here is everything that you require to know about that.

What is IKEv2?


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IKEv2 is an information security standard for virtual private networks (VPNs) that manages request and response operations. Its full name is Internet Key Exchange version 2.

It does this by establishing and managing the SA (Security Association) characteristic inside an authentication suite, which is typically IPSec because IKEv2 is basically integrated into it and predicated on it. 

This ensures that the traffic is safe to transmit. IKEv2 is the upgraded version of the earlier IKE protocol, which Microsoft created in collaboration with Cisco.

How Does IKEv2 Function?

IKEV2 relies largely on IPSec to protect VPN client-to-server communication. This explains why the protocol is frequently referred to as IKEv2/IPSec.

IKEv2/IPSec protects and enables the transfer of encryption keys, as its name implies.

In a word, IKEv2 creates a security association (SA) that is responsible for the negotiation of security keys that are utilized by the VPN client as well as the VPN server.

After IKEv2 has confirmed the validity of the security association, a secure tunnel is established, which causes the peers to begin exchanging encrypted information.

IKEv2/IPSec employs a more secure 256-bit encryption than other protocols. It supports VPN ciphers, including AES, ChaCha20, and Camellia.

The VPN protocol also uses the well-known Diffie-Hellman Key Exchange algorithm, which enables the safe exchange of private keys.

It’s also important to note:

  • IKEv2 enables Perfect Forward Secrecy (PFS) for information security and integrity.
  • IKEv2/IPSec utilizes UDP packets in addition to port 500.
  • X.509 certificates are used for authentication by IKEv2
  • IKEv2 integrates effectively with open-source software like OpenIKEv2, StrongSwan, OpenSwan, and others.

There are four types of IKEv2 messages and exchanges:


This first communication originates from the endpoint of the VPN tunnel that begins the link and is sent to the other end to configure the shared security parameters.

It generates the IKE SA; this procedure must conclude before the subsequent one can begin.

Activities associated with this transaction include the negotiation of SA security settings, Diffie-Hellman keys, cryptography techniques, and nonces.

To authenticate the message, the initiator generates a nonce, which is just a random number. A protocol for the exchange of security keys is known as Diffie-Hellman.

Remembering that this exchange is bidirectional, the initiator transmits IKE SA INIT, and the receiver sends IKE SA INIT in return.


The following exchange follows the initial one. Similar to the first, it needs to complete its protocol before either end can send more messages.

This exchange involves communicating and verifying the identities of both endpoints of the portal.

At this point in the process, authentication takes place, with both sides presenting the authentication information discussed and agreed upon in the previous stage.

Confirmation of both parties after this stage establishes the CHILD SA, which is any SA agreed throughout the first two exchange platforms.


It performs the same purpose as the Quick mode exchange in IKEv1 when extra child SAs are needed or if the IKE SA or one of the children SAs has to be rekeyed.

As depicted in the diagram, there are only two transmissions in this exchange; nevertheless, this exchange is repeated for each rekey or new SA.

IKEv2 Fragmentation

Multiple certifications can cause IKEv2 packets to exceed the route MTU when certificate-based verification is utilized.

If the size of an IKE message exceeds the MTU of the path, the signals are split at the IP level.

Certain network hardware, such as NAT routers, prohibits the passage of IP fragments, hence preventing the construction of IPsec tunnels.

IKEv2 is capable of operation in contexts where IP fragments may be banned, and users would not be capable of establishing an IPsec protection connection without the help of IKEv2 messaging fragmentation, which is detailed in RFC 7383, Internet Key Exchange Protocol Version 2 (IKEv2) Message Fragmentation (SA). 

IKEv2 fragmentation divides a massive IKEv2 communication into a collection of smaller ones, preventing fragmentation at the IP level.

When communication is fragmented, it is done so before the message itself is secured and authorized.

It ensures that each fragment is properly encrypted and verified in its own right. The communication fragments are gathered, validated, decrypted, and reassembled on the receiving end.

When to Use IKEv2

IKEv2 is a more recent and robust protocol for building encrypted communications between connected devices.

The majority of VPN service suppliers make use of it in order to create the first connection with the devices that their customers are using before transferring the traffic to OpenVPN or other protocols.

Confidential communication is established between your computer and the VPN server via a Diffie–Hellman key exchange mechanism.

IKEv1 was originally conceived as an alternative for Cisco’s proprietary IPSec VPN protocol in terms of compatibility. It fulfilled this function admirably and is still widely employed.

Furthermore, it contains significant security flaws that give it an unsafe option for certain VPN connections. IKEv2 was created to address these difficulties.

It employs stronger cryptography (such as mandating the usage of AES-256 instead of DES or 3DES) and provides a number of security enhancements over IKEv1.

In addition, MOBIKE, a technology that enables the construction of redundant Vpn tunnels from endpoints behind NAT firewalls, is also supported.

This makes it a perfect option for phone devices that access the web via wireless hotspots or other unreliable networks.

IKEv1 vs IKEv2

In 1998, a new version of the Internet Key Exchange protocol was created as a follow-up to the original.

Numerous advances over its predecessor render IKEv1 obsolete.

  • This means that IKEv2 needs lesser messages to be transmitted between the secure tunnel sites.
  • IKEv1 doesn’t support NAT traversal.
  • IKEv2 supports Extensible Authentication Protocol (EAP).
  • Because IKEv2 includes the Mobility and Multihoming Protocol, or MOBIKE, it can sustain secure internet connectivity even if the user changes IP addresses. There is no requirement to rejoin the VPN, eliminating the possibility of data breaches.
  • IKEv1 requires additional security associations to construct a VPN tunnel, resulting in a considerable bandwidth reduction.
  • IKEv1 supports fewer ciphering techniques than IKEv2
  • It is not possible to bring IKE version 2 down with a denial-of-service attack. Before processing data traffic, similar to IKEv1, it checks the existence of the requester.
  • All IKEv2 message types are described as request-response pairs, which increases the protocol’s reliability.
  • IKEv2 implements asymmetric authentication.

Features of IKEv2 VPN Protocol

VPN tunnel

IKE aims to generate identical symmetric encryption independently for all communication parties.

The standard Internet Protocol packets used for transporting data among VPN partners can be encrypted and decrypted using this key.

IKE creates a VPN tunnel by identifying both parties and negotiating encrypted and security protocols. IKE negotiations result in the Security Association (SA).

Perfect Forward Secrecy

IKEv2’s PFS function guarantees the absolute safety and security of your data. It accomplishes this by ensuring that keys are not duplicated and sessions expire.

Control Network Traffic

If one of the network interfaces on a multi-homed host stops functioning, it is possible to switch to another network connection using MOBIKE.

Robust Security

The standard provides superior security and even enables additional encryption ciphers for optimum protection.

Therefore, it is appropriate for activities requiring robust security, such as torrent downloading and browsing the dark web.

Blazing Speed

IKEv2/IPSec is an exception to the rule that a protocol with a high level of protection is probably to have a low transmission rate.

The protocol provides robust security measures while preserving good speed.

Consequently, it will efficiently secure your data and execute data-intensive applications such as playing games, torrenting, and multimedia streaming.


IKEv2/IPSec is compatible with most operating systems; however, it is optimized for smartphones.

Because of this, it is the official protocol for iOS. Additionally, it is accessible with a variety of routers.

Other important characteristics of the IKEv2 include:

  • It is compatible with the most current encryption methods.
  • Typically, the IKE operates in the local storage, which is the portion of system memory devoted to application servers. In the meantime, the IPsec stack operates in kernel storage or the operating system’s base, which boosts performance.
  • In order to execute the IKE protocol, UDP packets with port 500 are used.
  • Four to six packets are used to create the SA.
  • IKE’s origins may be traced to three security standards: ISAKMP, SKEME, and OAKLEY.
  • When IKEv2 is used in a VPN, MOBIKE is supported. In addition to the benefits mentioned above, it provides certainty to the protocol stack and enhances the experience of the mobile VPN connection.
  • IKEv2 is compatible with PFS (Perfect Forward Secrecy).

Is IKEv2 Secure?

IKEv2 is commonly acknowledged to be trustworthy. It employs powerful encryption ciphers and the Diffe-Hellman algorithm for key exchange security.

PFA, which is essential for long-term data security, is also supported by this technology. PFA permits the user and VPN router to negotiate new session-specific keys.

In other words, if the login details were hacked, they could not be utilized to decode data from previous sessions.

Leaked information revealed that the NSA had cracked IKEv2, raising questions about whether it lived up to its name.

Encryption technologies such as SSL/TLS prohibit third-party interference.

Legislators have argued that firms should be permitted to wiretap and decode encrypted government documents.

Consequently, there is little uncertainty that a collection of intelligence organizations such as the NSA has not used its substantial resources to uncover flaws in technology that permit them to monitor digital information.

Is IKEv2 Easy To Install & Configure?


In most cases, configuring IKEv2 is not too difficult. It is natively compatible on a variety of platforms, such as Windows 7+, macOS 10.11+, and the majority of mobile devices (even BlackBerry!).

If you wish to set up an IKEv2 server on your own, though, things become more challenging. IPSec is a more complicated protocol than OpenVPN; hence it will require additional settings.

What Is IKEv2 Best Suited For?

As a result of its advanced reconnecting features, IKEv2 became incredibly popular among phone devices.

Changing from a mobile network to a Wi-Fi network does not expose you to the risk of data leakage. It is great for frequent travelers who desire robust security for their mobile gadgets.

IKEv2 Advantages And Disadvantages


  • One of the fastest VPN protocols available. More quickly than L2TP and PPTP.
  • Extremely safe, as it encodes with sophisticated ciphers such as AES, Camellia, and 256-bit security protocols.
  • Provides a robust and steady connection and enables consumers to remain connected to the VPN when transferring between connections.
  • BlackBerry smartphones only support the OpenVPN protocol.


  • As UDP Port 500 is used by IKEv2, the VPN may be blocked by a firewall or by a network administrator.
  • Native integration is only available for Mac and iOS; it is not available for Windows, Android phones, or Linux.

The Bottom Line

Now you know what IKEv2 is.

The IKEv2 VPN standard is robust, secure, reliable, and quick. IKEv2 has no notable drawbacks.

Therefore, you may securely utilize it whenever you require it to encrypt internet traffic.

As described, IKEv2 is simple to configure and is supported by the majority of VPN suppliers’ mobile apps.

Moreover, because of its reliability when switching networks, it is ideally suited for use on smartphones.

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Written by Trevor Cooke

Trevor Cooke is an accomplished technology writer with a particular focus on privacy and security. He specializes in topics such as VPNs, encryption, and online anonymity. His articles have been published in a variety of respected technology publications, and he is known for his ability to explain complex technical concepts in a clear and accessible manner.

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