What IP address allocation should be used in a firewall rule to give access to a single host?

The correct choice involves using the notation "192.0.2.0/32," which signifies a specific allocation of an IP address that refers to a single host. The "/32" indicates that all 32 bits of the IP address are fixed, meaning it represents one unique IP address with no additional hosts in the range. This is important when implementing a firewall rule for access because it allows traffic to be explicitly allowed or denied for that exact IP, ensuring strict control over which device on a network can communicate through the firewall.

In contrast, the other options represent broader ranges of IP addresses. For example, "192.0.2.0/16" includes a substantial range of addresses, from "192.0.0.1" to "192.0.255.254," allowing many hosts. Similarly, "192.0.2.0/24" covers a range from "192.0.2.1" to "192.0.2.254," and "192.0.2.0/28" encompasses even more than that, allowing for multiple hosts within their respective ranges. Therefore, when the goal is to target a single host, using "/32" is the most effective method for precise