CIDR子网掩码地址数通配符
/32255.255.255.25510.0.0.0
/31255.255.255.25420.0.0.1
/30255.255.255.25240.0.0.3
/29255.255.255.24880.0.0.7
/28255.255.255.240160.0.0.15
/27255.255.255.224320.0.0.31
/26255.255.255.192640.0.0.63
/25255.255.255.1281280.0.0.127
/24255.255.255.02560.0.0.255
/23255.255.254.05120.0.1.255
/22255.255.252.01,0240.0.3.255
/21255.255.248.02,0480.0.7.255
/20255.255.240.04,0960.0.15.255
/19255.255.224.08,1920.0.31.255
/18255.255.192.016,3840.0.63.255
/17255.255.128.032,7680.0.127.255
/16255.255.0.065,5360.0.255.255
/15255.254.0.0131,0720.1.255.255
/14255.252.0.0262,1440.3.255.255
/13255.248.0.0524,2880.7.255.255
/12255.240.0.01,048,5760.15.255.255
/11255.224.0.02,097,1520.31.255.255
/10255.192.0.04,194,3040.63.255.255
/9255.128.0.08,388,6080.127.255.255
/8255.0.0.016,777,2160.255.255.255
/7254.0.0.033,554,4321.255.255.255
/6252.0.0.067,108,8643.255.255.255
/5248.0.0.0134,217,7287.255.255.255
/4240.0.0.0268,435,45615.255.255.255
/3224.0.0.0536,870,91231.255.255.255
/2192.0.0.01,073,741,82463.255.255.255
/1128.0.0.02,147,483,648127.255.255.255
/00.0.0.04,294,967,296255.255.255.255

IP 地址类 IP Address Classes

Class地址段
A0.0.0.0 - 127.255.255.255
B128.0.0.0 - 191.255.255.255
C192.0.0.0 - 223.255.255.255
D224.0.0.0 - 239.255.255.255
E240.0.0.0 - 255.255.255.255

保留（私有）地址段

Class A10.0.0.0 - 10.255.255.255
Class B172.16.0.0 - 172.31.255.255
Class C192.168.0.0 - 192.168.255.255
localhost127.0.0.0 - 127.255.255.255
zeroconf169.254.0.0 - 169.254.255.255
内部路由 (RFC 6598)100.64.0.0 - 100.127.255.255

十进制到二进制对应表

十进制子网掩码对应二进制十进制通配符对应二进制
2551111 111100000 0000
2541111 111010000 0001
2521111 110030000 0011
2481111 100070000 0111
2401111 0000150000 1111
2241110 0000310001 1111
1921100 0000630011 1111
1281000 00001270111 1111
00000 00002551111 1111

术语表

通配符掩码在用二进制表示的通配符掩码中，0 表示要检查的位，1 表示不需要检查的位。
CIDRClassless Inter Domain Routing 提供了比传统的 IP 地址类更细致的地址划分。CIDR 标记写法是 /XX