IKEv2
acronymsecuritynetworking
Internet Key Exchange version 2: the negotiation that authenticates both ends of an IPsec tunnel and establishes the keys, replacing a first version whose complexity was its main flaw.
Version 1 grew several negotiation modes with subtly different security properties, and aggressive mode in particular could expose a hash of the pre-shared key to a passive observer. Version 2 collapsed that into one exchange of four messages, made the request-response pairing explicit so that retransmission and dead-peer detection actually work, and built in the NAT traversal and mobility handling that version 1 had bolted on. For an operator the practical differences are that a version 2 tunnel survives a change of address - a laptop moving from wired to mobile - and that the failure modes are legible, because each exchange has a matching response rather than a state machine to infer. It is the default for any new deployment, and the reason a remote-access migration away from a browser-based tunnel usually lands here.
Also known as: ikev2, internet key exchange version 2, ike v2