IKE or Internet key exchange is the protocol responsible for negotiating the IPsec tunnel characteristics between two IPsec peers. IKE's responsibilities in the IPsec protocol include
Negotiating protocol parameters
Exchanging public keys
Authenticating both sides
Managing keys after the exchange
IKE solves the problems of manual and unscalable IPsec implementation by automating the entire key-exchange process. This is one of IPsec's critical requirements.
IKE, like IPsec, is also a combination of three different protocols:
SKEME— Provides a mechanism for using public key encryption for authentication purposes.
Oakley— Provides a mode-based mechanism for arriving at an encryption key between two IPsec peers.
ISAKMP— Defines ...