CompTIA Network+ N10-009 Practice Question

IPSec is the correct answer because it is designed to securely exchange data over public networks such as the internet by encrypting and authenticating IP packets. This protocol includes provisions for establishing mutual authentication between agents at the beginning of a session and negotiation of cryptographic keys to be used during the session, making it ideal for VPN tunnels. Generic Routing Encapsulation (GRE) is used to encapsulate a wide variety of protocol packet types inside IP tunnels, facilitating VPN operations but does not inherently provide encryption or security mechanisms. User Datagram Protocol (UDP) is often used by applications that require a fast, connectionless transmission without built-in security features. Transmission Control Protocol (TCP), although reliable, does not provide encryption or security functions required for secure tunneling.