What feature enables FortiGate to encrypt traffic between its interfaces and external networks?

The feature that enables FortiGate to encrypt traffic between its interfaces and external networks is IPsec tunnels. IPsec (Internet Protocol Security) provides a framework for securing Internet Protocol communications by authenticating and encrypting each IP packet in a communication session. This allows for secure data transfer and private communication across untrusted networks, ensuring that sensitive information remains confidential and integrity is maintained.

IPsec tunnels can be configured to protect not just the data packets but also to ensure secure connections between two gateways or between a user and a gateway. By establishing an encrypted tunnel, FortiGate can safeguard communication against interception or tampering, making it a critical feature for organizations that require secure connections to external networks.

In contrast, other options serve different purposes:

VPN connections can involve various protocols, but IPsec specifically refers to the encryption method used within those connections. SSL VPNs provide secure remote access, predominantly for web applications, but they work differently from IPsec tunnels. Network Address Translation (NAT) does not provide encryption; rather, it is used for mapping internal IP addresses to external addresses, facilitating seamless communication without providing confidentiality for the data being transmitted.