What mode of ESP does Jacob need to use to encrypt the IP traffic?

The agency Jacob works for stores and transmits vast amounts of sensitive government data that cannot be compromised. Jacob has implemented Encapsulating Security Payload (ESP) to encrypt IP traffic. Jacob wants to encrypt the IP traffic by inserting the ESP header in the IP datagram before the transport layer protocol header.

What mode of ESP does Jacob need to use to encrypt the IP traffic?
A . He should use ESP in transport mode.
B . Jacob should utilize ESP in tunnel mode.
C . Jacob should use ESP in pass-through mode.
D . He should use ESP in gateway mode

View Answer

Answer: B

Explanation:

Jacob needs to use ESP in tunnel mode to encrypt the IP traffic. In tunnel mode, the entire original IP packet, including both the payload and the IP header, is encrypted and then encapsulated within a new IP packet with a new IP header123. This mode is particularly useful for encrypting traffic between different networks, such as in a site-to-site VPN, where the data and security endpoints may differ from the original source and destination IP addresses2. Transport mode, on the other hand, would only encrypt the payload of the IP packet, leaving the original IP header unencrypted123. Since Jacob’s goal is to encrypt the entire IP datagram before the transport layer protocol header, tunnel mode is the appropriate choice.

Reference: The information provided here is consistent with the principles of IPsec and ESP as described in various networking resources, including the Twingate article on IPsec Tunnel Mode vs. Transport Mode1, TutorialsPoint’s explanation of ESP in tunnel and transport mode2, and the STIGViewer’s guidelines on IPsec VPN Gateway requirements3.