CCNA: Cisco Certified Network Associate — Question 1042

Which encryption mode is used when a packet is sent from a site-to-site VPN connection where the source and destination IP address portion of a packet is unencrypted?

Answer options

• A. PPTP
• B. Secure Shell
• C. Transport
• D. PPPoE

Correct answer: C

Explanation

The correct answer is C, Transport mode, which encrypts the payload of the packet but not the header, allowing the IP addresses to remain visible. Options A and B refer to different protocols that do not specifically relate to the encryption mode in question, while D, PPPoE, is a protocol for encapsulating PPP frames in Ethernet frames and does not pertain to encryption modes.