I am refreshing my understanding of IPSEC.
IPSec is an IETF defined set of security services that use open standards to provide data confidentiality, integrity, and authentication between peers.
IPsec involves two security services:
- Authentication Header (AH): This authenticates the sender and it discovers any changes in data during transmission; incompatible with NAT.
- Encapsulating Security Payload (ESP): This not only performs
authentication for the sender but also encrypts the data being sent
(confidentiality).
Why would anyone ever use AH? ESP does it plus more. In other words, why is AH specified? Also, has anyone ever deployed or used AH-only IPSEC?