What security measure can be enhanced by blocking all traffic from outside a designated region without altering port configurations?

The correct answer is the Web Application Firewall (WAF). A WAF is specifically designed to protect web applications by filtering and monitoring HTTP traffic between a web application and the Internet. By blocking all traffic from outside a designated region, a WAF can enhance security by allowing only trusted traffic to access the application, thereby reducing the risk of attacks that may originate from untrusted geographical areas.

This method of restricting traffic based on geographic location, often referred to as geo-blocking, can help mitigate threats such as Distributed Denial of Service (DDoS) attacks or attempts by hackers to exploit vulnerabilities in web applications. Importantly, this approach does not require changes to port configurations, as it operates at the application layer rather than the network layer.

Other security measures like firewalls can also block traffic, but they typically focus on port and protocol filtering rather than being application-specific. Virtual Private Networks (VPNs) are primarily used for secure remote access, and Intrusion Detection Systems (IDS) are intended for monitoring and alerting rather than actively blocking traffic. Therefore, the unique capacity of a WAF to enhance security through geolocation-based traffic filtering makes it the best answer to the question.