Networking :: Subnetting

General
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1

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?

  1. 172.16.1.100
  2. 172.16.1.198
  3. 172.16.2.255
  4. 172.16.3.0

Please help me to answer the question.

3

@pravat.training As per my calculation, Option 1,2,3 are valid id’s/Range for LAN Interface.
Kindly correct me if i am wrong.

Umesh
Thanks…!!!

4

@Umeshkumar Thanks for replying. I also need to understand the process to solve the question.

5

Hi @pravat.training >> As per the calculation the above mentioned IP(Class B) is in the 172.16.2.0 subnet with a subnet mask: 255.255.254.0 (i.e. /23) so it means the gap is 2.0 so the next subnet is 172.16.4.0/23 that’s why the the valid host IP range in the mentioned subnet(172.16.2.0/23) is: 172.16.2.1 to 172.16.3.254. (Total valid hosts are 2 power 9 =512-2= 510). Here router has first valid host IP assigned on the E0 interface. So the correct answer should be: option 3 & 4 because 1 & 2 are not in valid host IP range. Please correct me if I am wrong.
Thanks!

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6

Hi @parag_gajpure. The answer is correct. Thanks for replying with details.

1 Like
7

Sorry my bad. Option 1 and 2 will come in first subnet (172.16.0.0 - 172.16.1.255). valid ip
range (172.16.0.1 - 172.16.1.254)
and Option 3 & 4 will come in second subnet (172.16.2.0 - 172.16.3.255) valid ip range (172.16.2.1 - 172.16.3.254). So option 2&3 is correct…!!!

@parag_gajpure thanks for clarity…!!!

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8

@parag_gajpure Is correct