Final answer:
The IPsec protocol designed to authenticate that packets received were actually sent from the claimed source is the A. Authentication Header (AH). It ensures data origin authentication and data integrity.
Step-by-step explanation:
The IPsec protocol that authenticates that packets received were sent from the source is A) AH (Authentication Header). The AH protocol provides data origin authentication, which ensures that the data was sent by the actual sender. It also provides data integrity, ensuring that the data has not been tampered with in transit. Additionally, AH can optionally provide anti-replay services, which protect against unauthorized repeated transmissions.
On the other hand, B) ESP (Encapsulating Security Payload) provides confidentiality, data origin authentication, and data integrity, but its primary purpose is to encrypt the payload and not just authenticate. C) IKE (Internet Key Exchange) is used for setting up security associations and key exchanges. D) SSL (Secure Sockets Layer) is used for securing communication over the web but is not an IPsec protocol.