2. Features and general operation of the IPsec protocol suite

To protect against eavesdropping and identity theft, the IETF's IPsec group has built security mechanisms into the IPv4 and IPv6 protocols to :

• encrypt IP packets (content only or the entire packet) ;

• introduce an authenticator to certify the sending equipment and check the integrity of all or part of the IP packet.

• As the security mechanisms are identical for IPv4 and IPv6, we will first look at IPv4; the particularities of IPsec in an IPv6 environment are presented at 7