A network administrator wants to implement a method of securing internal routing. Which of the following should the administrator implement?

A DMZ (Demilitarized Zone) is a network segment designed to host publicly accessible servers, providing a layer of security by isolating them from the internal network, but it does not inherently secure internal routing protocols or traffic.

Network Address Translation (NAT) modifies IP addresses in packet headers, primarily for address conservation and obfuscation, but it does not encrypt or secure routing information itself.

A Virtual Private Network (VPN) establishes an encrypted tunnel over an untrusted network, protecting the confidentiality and integrity of data, including routing updates or traffic, between internal network segments or remote sites. This encryption ensures that internal routing information or data is secured from eavesdropping or tampering as it traverses an unsecure medium.

Port Address Translation (PAT) is a form of NAT that maps multiple private IP addresses to a single public IP address using different port numbers, serving for address translation rather than securing routing protocols or traffic.