CREST Practitioner Security Analyst (CPSA) Practice

What is the CIDR notation for Class B IP addresses?

1. /16

2. /24

3. /8

4. /12

The correct answer is: /16

The CIDR (Classless Inter-Domain Routing) notation for Class B IP addresses is indeed /16. This notation signifies that the first 16 bits of the IP address are used for the network part, while the remaining bits are available for host addresses within that network. Class B IP addresses range from 128.0.0.0 to 191.255.255.255 and include a total of 65,536 possible addresses within each Class B network (2^16), which accommodates a significant number of hosts, making it suitable for medium to large-sized networks. CIDR notation was established to improve the allocation of IP addresses and to facilitate better route aggregation on the internet. The /16 indicates a subnet mask of 255.255.0.0, clearly defining the division between the network and host portions of the address. In contrast, the other options reflect notations that are associated with different classes of IP addresses. For instance, /24 corresponds to Class C addresses, which utilize the first 24 bits for the network part, allowing for a greater number of smaller networks but fewer hosts per network. Similarly, /8 corresponds to Class A networks, indicating that the first 8 bits are for the network, and /