一些掩码的换算
2008-11-04 | 16:51a.b.c.d
a=8,b=16,c=24,d=32
| 掩码 | A | B | C | D | 值 |
| 254 | 7 | 15 | 23 | 31 | -1 |
| 252 | 6 | 14 | 22 | 30 | -2 |
| 248 | 5 | 13 | 21 | 29 | -3 |
| 240 | 4 | 12 | 20 | 28 | -4 |
| 224 | 3 | 11 | 19 | 27 | -5 |
| 192 | 2 | 10 | 18 | 26 | -6 |
| 128 | 1 | 9 | 17 | 25 | -7 |
| 0 | - | 8 | 16 | 24 | -8 |
上面这串数字要结合 abcd那里来分析，比如 255.240.0.0 代表b位有值，那么就按照 B来计算，所以真实掩码值就是 12 ； 而255.255.128.0 则代表c有值，则真实掩码为 17 这样方便快速换算！！！
标签：ip, 换算, 掩码相关日志
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