Devices for Regional Office Connectivity

D.

The most likely device that would be added at each regional office is a firewall (option D).

Firewalls act as a barrier between an organization's internal network and external networks, such as the Internet. They filter traffic based on predefined rules, allowing only authorized traffic to pass through while blocking unauthorized traffic.

In this scenario, with the regional offices moving away from MPLS network to high-speed connections and VPNs, the company would need to ensure the security of their network. By adding a firewall at each location, the organization can establish a secure connection between the regional offices and the main campus.

Option A, Security Information and Event Management (SIEM), is a tool used to centralize security events and logs from various devices in a network. While it is a valuable tool for monitoring and detecting security threats, it is not essential in this scenario.

Option B, Intrusion Detection System/Intrusion Prevention System (IDS/IPS), is a system that detects and prevents unauthorized access to a network. While it is a useful tool in protecting the network, it is not the most likely device to be added in this scenario.

Option C, a proxy server, is an intermediary server between a user and the Internet. It can be used to improve network performance and security by filtering requests and caching frequently accessed content. However, it is not necessary in this scenario since the organization is moving towards VPN connections.

Option E, a router, is a networking device that connects different networks together and routes data between them. While a router is necessary for network connectivity, it is not the most likely device to be added in this scenario since the organization is moving towards VPN connections and needs a higher level of security than a router can provide.

Therefore, the most likely device to be added at each regional office is a firewall.