Cisco Certified Network Associate (CCNA) Practice Exam

Which subnet mask would be appropriate for a network address range to be subnetted for up to eight LANs, with each LAN containing 5 to 26 hosts?

1. 255.255.255.0

2. 255.255.255.128

3. 255.255.255.192

4. 255.255.255.224

The correct answer is: 255.255.255.224

To determine the appropriate subnet mask for a network address range that needs to support up to eight LANs, each containing between 5 to 26 hosts, it's essential to consider both the required number of subnets and the needed number of hosts per subnet. Using a subnet mask of 255.255.255.224 allows for a total of 8 subnets (2^3 = 8) because 3 bits are borrowed from the host part in a Class C address (which has a default mask of 255.255.255.0). Each of these subnets can support up to 30 usable hosts (2^5 - 2 = 30), where 5 bits remain for host addresses. The subtraction of 2 is necessary to account for the network and broadcast addresses, which cannot be assigned to hosts. This setup perfectly aligns with the requirements where you need to create 8 LANs and each LAN needs to accommodate between 5 to 26 hosts. The other subnet masks do not meet the requirements as well as the chosen subnet mask: - A mask of 255.255.255.0 provides only 1 subnet with a maximum of 254 hosts, which is more than needed but doesn't allow for the