What protocol is used to create a secure connection for a VPN?

The protocol used to create a secure connection for a VPN is IPSec. This protocol works at the network layer and is designed to secure Internet Protocol (IP) communications by authenticating and encrypting each IP packet in a communication session. IPSec provides essential security services such as confidentiality, integrity, and authentication, making it suitable for establishing VPNs that require secure data transmission over potentially untrusted networks.

IPSec can be used in two modes: transport mode, where only the payload of the IP packet is encrypted and authenticated, and tunnel mode, where the entire IP packet is encrypted and then encapsulated into a new IP packet with a different header. This flexibility allows it to protect the data of various applications, securing communication between sites or users effectively.

In contrast, while L2TP is often paired with IPSec for added security, it is primarily a tunneling protocol and does not provide encryption on its own. SSL is also used for securing connections, particularly in web environments (SSL/TLS), but it is not typically employed for VPNs in the same way as IPSec. HTTP does not offer any security features and is simply the protocol used for transmitting data over the web in an unsecured manner. Thus, IPSec stands out as the correct