*マスクビット数とネットマスクの対応表 [#v4a8eaaa] |ビット数|ネットマスク|ネットマスク|使えるアドレス数| ||(16進)| (10進) || |/8 (Class A)|0xff000000|255.0.0.0 |16,777,214| |/9 |0xff800000 |255.128.0.0 |8,388,604 | |/10 |0xffc00000 |255.192.0.0 |4,194,302| |/11 |0xffe00000 |255.224.0.0 |2,097,150| |/12 |0xfff00000 |255.240.0.0 |1,048,574| |/13 |0xfff80000 |255.248.0.0 |524,286| |/14 |0xfffc0000 |255.252.0.0 |262,144| |/15 |0xfffe0000 |255.254.0.0 |131,072| |/16(Class B) |0xffff0000 |255.255.0.0 |65,534| |/17 |0xffff8000 |255.255.128.0 |32,766| |/18 |0xffffc000 |255.255.192.0 |16,382| |/19 |0xffffe000 |255.255.224.0 |8,190| |/20 |0xfffff000 |255.255.240.0 |4,094| |/21 |0xfffff800 |255.255.248.0 |2,046| |/22 |0xfffffc00 |255.255.252.0 |1,022| |/23 |0xfffffe00 |255.255.254.0 |510| |/24(Class C) |0xffffff00 |255.255.255.0 |254| |/25 |0xffffff80 |255.255.255.128 |126| |/26 |0xffffffc0 |255.255.255.192 |62| |/27 |0xffffffe0 |255.255.255.224 |30| |/28 |0xfffffff0 |255.255.255.240 |14| |/29 |0xfffffff8 |255.255.255.248 |6| |/30 |0xfffffffc |255.255.255.252 |2| |/31 (無意味) |0xfffffffe |255.255.255.254 |0| |/32 (ホスト) |0xffffffff |255.255.255.255 |(1)|