CompTIA Server+ Exam Practice: IP Address Configuration

Network Address: 199.90.10.32/28

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Question

A server administrator has been given the following information from the network team in order to configure IP addresses on a new server: Network Address: 199.90.10.32/28 The network team also instructed the server administrator to use the LAST usable address on the given network.

Which of the following IP address/subnet mask combinations should the server administrator use?

Answers

Explanations

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A. B. C. D.

C.

The network address provided is 199.90.10.32/28. The /28 indicates that the subnet mask is 255.255.255.240. This subnet mask provides 16 IP addresses in total, with 14 usable addresses for devices on the network.

To find the last usable address, we need to determine the range of usable addresses within the subnet. The first usable address is always the one immediately following the network address, while the last usable address is always the second to last address in the subnet.

To calculate the range of usable addresses, we can use the formula: 2^n - 2, where n is the number of host bits in the subnet mask.

In this case, there are 4 host bits in the subnet mask (32 - 28 = 4), so we can calculate the number of usable addresses as: 2^4 - 2 = 14.

The range of usable addresses for this subnet is therefore: 199.90.10.33 - 199.90.10.46

To find the last usable address, we simply need to take the second to last address in the range, which is: 199.90.10.45

So the correct answer is A. 199.90.10.49, 255.255.255.240, since this IP address is within the subnet range and is the last usable address on the subnet.