What Is IKEv2 VPN? All You Need to Know About the IKEv2 Protocol

What Is IKEv2 VPN? All You Need to Know About the IKEv2 Protocol

Internet security has never been as vital as it is in this digital age. Malicious internet entities are on the increase. It has now become the duty of everyone who owns a device that connects to the internet to ensure their personal or corporate data on those devices are safe from unauthorized access. 

A Virtual Private Network (VPN) is a way to keep your devices from malicious entities that may want to spy on your internet connection and ultimately steal your data or destroy your files. 

VPNs have different protocols to ensure security: SSL/TLS, IPsec, IKEv2, PPTP, L2TP, SSH, and OpenVPN. In this review, we take a look at the IKEv2 VPN.

Understanding IKEv2 VPN

The Internet Key Exchange Version 2 (IKEv2) is one of the tunneling protocols VPNs implement to keep your connection safe. Cisco and Microsoft created IKEv2 in 2005 as an upgrade to IKEv1. In most cases, IKEv2 does not stand alone; it usually works together with IPsec encryption and is built around the IPsec protocol. 

IKEv2 handles creating a secure tunnel from the VPN client to the server. Using Security Associations, IKEv2 ensures a secure tunnel by negotiating a way to encrypt and authenticate IP packets between two endpoints safely.

It has support for strong data encryption ciphers such as Triple Data Encryption Standard (3DES), Advanced Encryption Standard (AES), ChaCha20, and Camellia; therefore, it is one of the safest out there. It also uses the Mobility and Multi-homing Protocol (MOBIKE), ensuring your tunnel connection remains active when switching networks. It is a brilliant feature for mobile device owners who may need to change networks regularly. 

IKEv2 supports the following devices: Blackberry, Windows 7+, macOS, and iOS. It also has various open-source versions. 

Here are some essential attributes of IKEv2:

1. Speed 

Setting up connections is swift and efficient. It also has a competent message exchange structure that favors better performance than most protocols; it offers higher output, giving you fast browsing speeds. 

2. Security

IKEv2 ensures data authentication, confidentiality, and integrity. Server certificate authentication and robust encryption protocols prevent malicious entities from penetrating the network. 

3. Reliability

MOBIKE protocol keeps connections active despite network changes. This is an improvement compared to its previous version, and it makes IKEv2 more reliable. 

How Does IKEv2 VPN Work?

You can implement IKEv2 in different scenarios: endpoint-to-endpoint, endpoint-to-gateway, and gateway-to-gateway. The purpose of this protocol is to generate an identical symmetric encryption key for the two ends of a tunnel. This key will be used by both ends to encrypt and decrypt IP packets sent each way, ensuring the security of the tunnel. 

It does this by establishing bilateral authentication through Security Associations (SA) at both end-points of the tunnel. There are usually two pairs of SAs at each end: one for outbound connections and another for inbound ones. The exchange of these pairs is what makes IKEv2 a response pair protocol. 

There are four kinds of IKEv2 exchanges/messages:


This first message comes from the VPN tunnel’s endpoint that initiates the connection and goes to the other end to establish security parameters both ends will use. It creates the IKE SA; this process must finish before the next one can start. This exchange’s activities include negotiating SA security parameters, Diffie-Hellman keys, encryption algorithms, and nonces. 

A nonce is simply a random number generated by the initiator along with the message for authentication. Diffie-Hellman is a security key exchange protocol. It is important to note that this exchange goes both ways; the initiator sends its IKE_SA_INIT and receives a response IKE_SA_INIT from the receiver.


The second exchange comes after the first. Like the first, it must finish its procedure before both ends can send any other messages. The following activities occur at this exchange: transmission and validation of the identity of both ends of the gateway. Authentication occurs at this stage; both ends present authentication information agreed on in the previous exchange. 

At the end of this stage, verification of both ends leads to establishing the CHILD_SA, which is simply any SA negotiated through the first two exchanges.


This exchange is for creating another CHILD_SA to use a new tunnel. This exchange initiates the negotiation of brand-new encryption algorithms, Diffie-Hellman keys, hashing algorithms, and nonces.


This exchange is for maintaining and monitoring the tunnel. Actions that can occur here include deleting SAs, monitoring SAs, sending informational messages, and error reporting. 

Establishing an IKEv2 VPN requires the first two exchanges to occur in the same order as above (IKE_SA_INIT then IKE_AUTH); the last two exchanges can happen in any order.

Advantages of IKEv2 VPN

Cisco and Microsoft made IKEv2 as an improvement to IKEV1. Some of the benefits of this protocol include the following:

1. Speed and Latency

IKEv2 is one of the fastest VPN protocols in use. It employs Network Address Translation-Traversal (NAT-T), which ensures that a firewall performing Network Address Translation (NAT) between the VPN client and server will not hinder the connection’s speed. 

It’s efficient architecture, and message exchange structure also contributes to its better performance. Applications that need low latency, like gaming applications, will enjoy using IKEv2 VPN since it runs on UDP port 500. 

2. Security 

It is also one of the most secure protocols since it supports a wide range of robust encryption, hashing, and authentication protocols. Verifying the identities of both ends of the VPN tunnel using certificates prevents attacks like Denial of Service (DoS) and Man-in-the-Middle (MITM). Perfect forward secrecy also prevents the exposure of encryption keys by frequently changing them.

3. Mobility and Reliability

Support for the MOBIKE protocol means you can easily change network connections and not worry about interruptions on your VPN connection. It is a great feature that permits retaining your connection while switching between Wi-Fi and mobile networks.

IKEv2 works very hard to restore lost links and maintain the stability of the connection. The ability to monitor the tunnel also makes it able to respond quickly to any interruptions. 

Disadvantages of IKEv2 VPN

The IKEv2 protocol has a few downsides outlined below:

1. Device Support

IKEv2 supports Windows, Blackberry, macOS, and iOS devices. Despite having several open-source versions, some VPN service providers are still hesitant to implement it. They will instead use other protocols that support several platforms for cross-compatibility. 

2. Firewall Restrictions

In trying to keep devices secure, network or firewall administrators might block UDP port 500, resulting in the IKEv2 VPN link being unable to connect.

3. Configuration

IKEv2 can require some intensive manual configurations in platforms it does not support. In most cases, VPN service providers will give instructions on how to implement it. 

IKEv2 Versus Popular VPN Protocols

1. IKEv2 vs. L2TP/IPsec

IKEv2 and L2TP (Layer Two Tunneling Protocol) typically work together with IPsec when presented by VPN service providers. This means they are at par in security since they use the same authentication suite.

When it comes to speed, IKEv2 takes the edge because L2TP/IPsec uses more system resources and has a slower negotiation process. It also supports the MOBIKE protocol making it more reliable and stable than L2TP/IPsec. Its limited support for several platforms makes it not as accessible as L2TP/IPsec.

2. IKEv2 vs. OpenVPN

OpenVPN is an open-source protocol that offers high levels of security. IKEv2 protects data at the IP layer, while OpenVPN protects data at the transport layer. Although the security difference between the two protocols is not much, OpenVPN is usually considered the more secure protocol. 

IKEv2 usually is faster than OpenVPN because it uses fewer system resources. OpenVPN can use UDP, but that will still not make it as fast as IKEv2. It’s easier for network administrators to block IKEv2 because it utilizes only UDP port 500, unlike OpenVPN that uses both TCP and UDP with ports 443  and 1194, respectively.

Both are relatively stable and reliable, but IKEv2 is more reliable on mobile devices than OpenVPN. With support for more platforms, OpenVPN wins when it comes to cross-platform compatibility. 


IKEv2 is a secure VPN protocol that often works best together with IPsec. It is fast, reliable, safe, and easy to use on native platforms. It is an exceptional choice for mobile VPN customers because it supports the MOBIKE protocol. The lack of support for several platforms is a significant drawback that entices VPN service providers to offer alternative protocols.