Table B-1: Common Subnet Masks and Their Host Counts
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Subnet Mask (Slash Prefix) | Subnet Mask (Dotted Decimal) | Network Bits in Subnet Mask | Host Bits in Subnet Mask | Hosts per Net |
/16 | 255.255.0.0 | 16 | 16 | 65,534 |
/17 | 255.255.128.0 | 17 | 15 | 32,766 |
/18 | 255.255.192.0 | 18 | 14 | 16,382 |
/19 | 255.255.224.0 | 19 | 13 | 8,190 |
/20 | 255.255.240.0 | 20 | 12 | 4,094 |
/21 | 255.255.248.0 | 21 | 11 | 2,046 |
/22 | 255.255.252.0 | 22 | 10 | 1,022 |
/23 | 255.255.254.0 | 23 | 9 | 510 |
/24 | 255.255.255.0 | 24 | 8 | 254 |
/25 | 255.255.255.128 | 25 | 7 | 126 |
/26 | 255.255.255.192 | 26 | 6 | 62 |
/27 | 255.255.255.224 | 27 | 5 | 30 |
/28 | 255.255.255.240 | 28 | 4 | 14 |
/29 | 255.255.255.248 | 29 | 3 | 6 |
/30 | 255.255.255.252 | 30 | 2 | 2 |
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