Subnetting

Correct Answer: 255.255.255.224

To create subnets with 20 hosts, 5 bits are required for host addressing, leaving 3 bits for subnetting. The new subnet mask would be 255.255.255.224.

Correct Answer: /28

To determine the correct subnet mask, we need to find one that can accommodate at least 14 usable IP addresses. A subnet with a /28 mask has 16 total IP addresses, but only 14 are usable as one address represents the subnet itself and another is reserved for the broadcast address. Here's why the other subnet masks are not suitable: A /29 subnet mask offers 8 IP addresses, but only 6 are usable with 2 reserved for the network and broadcast addresses, which is not enough. A /27 subnet mask offers 32 IP addresses, 30 usable, which is more than necessary and would lead to IP address waste. Finally, a /30 subnet mask provides only 4 total IP addresses, 2 usable, certainly not enough for the 14 required. Therefore, a /28 subnet mask is the most efficient choice that meets the requirement for 14 usable IP addresses.

Correct Answer: /27

To solve this, we need to determine the subnet mask that will provide at least five subnets each capable of hosting at least 28 devices. A /24 network contains 256 addresses (0-255), but for network and broadcast addresses, approximately 2 addresses per subnet cannot be used by devices. Let's analyze the given options: - A /27 subnet mask divides the original /24 network into 8 subnets (2^3=8) with 32 addresses each. Substracting the network and broadcast addresses, each /27 subnet can support up to 30 devices, which meets the requirement for at least 28 devices. Therefore, a /27 is the correct subnet mask because it provides both the necessary number of subnets and device addresses. Incorrect options: - A /28 subnet mask provides 16 subnets (2^4=16) with 16 addresses each. However, after accounting for the network and broadcast addresses, only 14 usable IP addresses remain, which is not enough for the required 28 devices per subnet. - A /26 subnet mask provides 4 subnets (2^2=4) with 64 addresses each. While this would be more than enough for 28 devices per subnet, it does not provide the necessary five subnets. - A /29 subnet mask provides 32 subnets (2^5=32) with only 8 addresses each. This is far fewer than the required 28 devices per subnet.