Subnetting Table

# of Host's - 2 Mask Slash Notation Class Formula Class C C C C C C Class B B B B B B B B B B B B B B Class A A A A A A A A A A A A A A A A A A A A A A

2*7 128 128 /17 /25 Slash Notation CIDR Value /25 /26 /27 /28 /29 /30 CIDR Value /17 /18 /19 /20 /21 /22 /23 /24 /25 /26 /27 /28 /29 /30 CIDR Value /9 /10 /11 /12 /13 /14 /15 /16 /17 /18 /19 /20 /21 /22 /23 /24 /25 /26 /27 /28 /29 /30

Subnetting Chart

2*6 64 192 /18 /26

2*5 32 224 /19 /27

2*4 16 240 /20 /28

2*3 8 248 /21 /29

Mask

Magic No. 256-Mask Magic No. 128 64 32 16 8 4 Magic No. 128 64 32 16 8 4 2 1 128 64 32 16 8 4 Magic No. 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4

Bits ON ON 1 2 3 4 5 6 ON 1 2 3 4 5 6 7 8 1 2 3 4 5 6 ON 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Bits OFF OFF 7 6 5 4 3 2 OFF 15 14 13 12 11 10 9 8 23 22 21 20 19 18 OFF 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2

255.255.255.128 255.255..255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252 255.255.128.0 255.255.192.0 255.255.224.0 255.255.240.0 255.255.248.0 255.255.252.0 255.255.254.0 255.255.255.0 255.255.255.128 255.255..255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252 255.128.0.0 255.192.0.0 255.224.0.0 255.240.0.0 255.248.0.0 255.252.0.0 255.254.0.0 255.255.0.0 255.255.128.0 255.255.192.0 255.255.224.0 255.255.240.0 255.255.248.0 255.255.252.0 255.255.254.0 255.255.255.0 255.255.255.128 255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252

2*2 4 252 /22 /30 Subnet / Block Size 2*Off Bits Block Size 128 64 32 16 8 4 Block Size 32,768 16,384 8,192 4,096 2,048 1,024 512 256 8,388,608 4,194,304 2,097,152 1,048,576 524,288 262,144 Block Size 8,388,608 4,194,304 2,097,152 1,048,576 524,288 262,144 131,072 65,536 32,768 16,384 8,192 4,096 2,048 1,024 512 256 128 64 32 16 8 4

2*1 2 254 /23

2*0 1 255 /24

No. of Subnets 2*On Bits Subnets 2 4 8 16 32 64 Subnets 2 4 8 16 32 64 128 256 2 4 8 16 32 64 Subnets 2 4 8 16 32 64 128 256 512 1,024 2,048 4,096 8,192 16,384 32,768 65,536 131,072 262,144 524,288 1,048,576 2,097,152 4,194,304

Host in each Subnet 2*On Bits - 2 Host 126 62 30 14 6 2 Host 32,766 16,382 8,190 4,094 2,046 1,022 510 254 8,388,606 4,194,302 2,097,150 1,048,574 524,286 262,142 Host 8,388,606 4,194,302 2,097,150 1,048,574 524,286 262,142 131,070 65,534 32,766 16,382 8,190 4,094 2,046 1,022 510 254 126 62 30 14 6 2

Prepared by Rajeev Dayal on 3/13/2007

(2*0) means 2 raise to power (0,1,2,3,4,5,6,7)

Binary Format

Example - (Range)

11111111.11111111.11111111.10000000 11111111.11111111.11111111.11000000 11111111.11111111.11111111.11100000 11111111.11111111.11111111.11110000 11111111.11111111.11111111.11111000 11111111.11111111.11111111.11111100 11111111.11111111.10000000.0 11111111.11111111.11000000.0 11111111.11111111.11100000.0 11111111.11111111.11110000.0 11111111.11111111.11111000.0 11111111.11111111.11111100.0 11111111.11111111.11111110.0 11111111.11111111.11111111.0 11111111.11111111.11111111.10000000 11111111.11111111.11111111.11000000 11111111.11111111.11111111.11100000 11111111.11111111.11111111.11110000 11111111.11111111.11111111.11111000 11111111.11111111.11111111.11111100 11111111.10000000.0.0 11111111.11000000.0.0 11111111.11100000.0.0 11111111.11110000.0.0 11111111.11111000.0.0 11111111.11111100.0.0 11111111.11111110.0.0 11111111.11111111.0.0 11111111.11111111.10000000.0 11111111.11111111.11000000.0 11111111.11111111.11100000.0 11111111.11111111.11110000.0 11111111.11111111.11111000.0 11111111.11111111.11111100.0 11111111.11111111.11111110.0 11111111.11111111.11111111.0 11111111.11111111.11111111.10000000 11111111.11111111.11111111.11000000 11111111.11111111.11111111.11100000 11111111.11111111.11111111.11110000 11111111.11111111.11111111.11111000 11111111.11111111.11111111.11111100

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