Which term refers to a connection method that integrates both authentication and encryption of IP packets?

The term that refers to a connection method integrating both authentication and encryption of IP packets is IPSEC. This protocol suite is specifically designed to secure Internet Protocol (IP) communications by ensuring data integrity, data origin authentication, and replay protection through the use of cryptographic security services.

IPSEC operates at the network layer and can be applied to the entire IP packet, protecting both the header and the payload. It achieves this through two main modes: transport mode, which encrypts only the payload, and tunnel mode, which encrypts both the header and the payload, thereby providing a secure communication channel between two endpoints.

This comprehensive approach makes IPSEC particularly suitable for virtual private networks (VPNs) and secure communications over untrusted networks like the internet, making it a standard choice for secure IP communications.

In contrast, the other options represent different protocols or methods, but they do not provide the combined capabilities of authentication and encryption at the IP packet level. For example, while PPTP and L2TP may provide tunneling, they do not inherently implement the same robust security features as IPSEC does. GRE, on the other hand, is a tunneling protocol but lacks built-in security features, such as encryption or authentication.