Which element protects and hides an internal network in an outbound flow?

NAT is the element that protects and hides an internal network in an outbound flow. NAT is a feature that translates the source or destination IP address or port of a packet as it passes through the firewall. NAT can protect and hide an internal network in an outbound flow by replacing the private IP addresses of the internal hosts with a public IP address of the firewall or another device, making them appear as a single entity to the external network. This prevents external hosts from directly accessing or identifying the internal hosts, and also conserves the public IP address space. DNS sinkholing, User-ID, and App-ID are not elements that protect and hide an internal network in an outbound flow, but they are related features that can enhance security and visibility. References: Palo Alto Networks Certified Software Firewall Engineer (PCSFE), [NAT Overview], [DNS Sinkholing Overview], [User-ID Overview], [App-ID Overview]