Internet Key Exchange (IKE) is the protocol used to negotiate and manage the security associations that protect IPsec traffic. In practice, IKE helps two endpoints authenticate each other, agree on cryptographic algorithms, exchange keys, and create the tunnel parameters that IPsec needs to encrypt and verify traffic.
IKE matters because it is the control plane for many VPN deployments. If IKE is misconfigured, attackers may weaken encryption, impersonate peers, or abuse exposed VPN gateways. Defenders harden it by using strong authentication, modern cipher suites, certificate-based identity, and strict access controls. In remote-access environments, IKE is often the step that turns a user login into an encrypted path into the network, so monitoring IKE negotiation failures, unusual proposals, and repeated connection attempts can help spot abuse.