# Networks

## Question

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### Problem with understanding subnetting class B address with /25 through /30

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Hello, I am having a very hard time understanding this problem which is explained but still not getting it.
Practice Example #7B: 255.255.255.192 (/26) Now, this is where Class B subnetting gets easy. Because the third octet has a 255 in the mask section, whatever number is listed in the third octet is a subnet number. However, now that we have a subnet number in the fourth octet, we can subnet this octet just as we did with Class C subnetting. Let’s try it: 172.16.0.0 = Network address 255.255.255.192 = Subnet mask Subnets? 210 = 1024. Hosts? 26 – 2 = 62. Valid subnets? 256 – 192 = 64. The subnets are shown in the following table. Do these numbers look familiar? Broadcast address for each subnet? Valid hosts? The following table shows the first eight subnet ranges, valid hosts, and broadcast address: Subnet 0.0 0.64 0.128 0.192 1.0 1.64 1.128 1.192
First host 0.1 0.65 0.129 0.193 1.1 1.65 1.129 1.193 Last host 0.62 0.126 0.190 0.254 1.62 1.126 1.190 1.254 Broadcast 0.63 0.127 0.1** 0.255 1.63 1.127 1.1** 1.255 Notice that for each subnet value in the third octet, you get subnets 0, 64, 128, and 192 in the fourth octet.

Is there someone who can explain this to me better?

Where I get confused is during finding the valid hosts it is going from 0.192 to 1.0 then to 1.64

Why not stop at 0.192? Hope I am making sense.

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