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127

Subnet

0.0

0.32

0.64

0.96

0.128

0.160

0.192

0.224

First host

0.1

0.33

0.65

0.97

0.129

0.161

0.193

0.225

Last host

0.30

0.62

0.94

0.126

0.158

0.190

0.222

0.254

0.31

0.63

0.95

0.127

0.159

0.191

0.223

0.255

# This next table shows the last eight subnets:

Subnet First host Last host Broadcast

255.0 255.32 255.64 255.96 255.128 255.160 255.192 255.1 255.33 255.65 255.97 255.129 255.161 255.193 255.30 255.62 255.94 255.126 255.158 255.190 255.222 255.31 255.63 255.95 255.127 255.159 255.191 255.223

255.224 255.225 255.254 255.255

Are you nuts? Subnet Class B addresses in our heads? If you think easier equals crazy, then, yes, I’m a few sails short, but it’s actually easier than writing it out—I’m not kidding! Let me show you how:

Answer: 256 – 224 = 32. 32 + 32 = 64. Bingo: 33 is between 32 and 64. However, remember that the third octet is considered part of the subnet, so the answer would be the 10.32 sub- net. The broadcast is 10.63, since 10.64 is the next subnet.

Answer: 256 – 192 = 64. 64 + 64 = 128. The subnet is 172.16.90.64. The broadcast must be 172.16.90.127, since 90.128 is the next subnet.