Your router has the following IP address on Ethernet0: 172.16.2.1/23. Which of the following can be valid host IDs on the LAN interface attached to the router?
172.16.1.100
172.16.1.198
172.16.2.255
172.16.3.0
A. 1 only
B. 2 and 3 only
C. 3 and 4 only
D. None of the above
The Correct Answer and Explanation is :
The correct answer is A. 1 only.
Explanation:
Let’s break down the provided IP address and subnet mask to determine which of the given host IDs are valid for the LAN interface.
- IP Address: 172.16.2.1
Subnet Mask: /23 The subnet mask of /23 corresponds to a netmask of 255.255.254.0. This means the first 23 bits of the IP address are used for the network portion, and the remaining 9 bits are used for the host portion. To understand the range of valid host IDs, let’s first look at the network address range. With the /23 subnet:
- The network address for the subnet would be 172.16.2.0 (the first address in the range).
- The broadcast address for the subnet would be 172.16.3.255 (the last address in the range). So, the valid range of host IPs within this subnet would be from 172.16.2.1 to 172.16.3.254.
Evaluating the given IPs:
- 172.16.1.100: This IP is in a different subnet. It’s part of the 172.16.0.0/23 range, which is not part of the 172.16.2.0/23 network. Thus, it cannot be a valid host ID in the given LAN.
- 172.16.1.198: This IP is also in the 172.16.0.0/23 subnet, not the 172.16.2.0/23 subnet. It is not a valid host ID on the current LAN.
- 172.16.2.255: This is the broadcast address for the 172.16.2.0/23 network. Broadcast addresses cannot be assigned to hosts, so this is not a valid host ID.
- 172.16.3.0: This is the network address for the 172.16.3.0/23 subnet. Network addresses are not assignable to hosts, so this is not a valid host ID.
Conclusion:
The only valid host ID in the given options that falls within the range of the 172.16.2.1 – 172.16.3.254 range is 172.16.1.100, which is outside this range, making none of the valid answers