IPv4地址范围以及子网范围计算
1. 分类IP范围
ClassRangeA0.0.0.0 - 10.255.255.255B128.0.0.0 - 191.255.255.255C192.0.0.0 - 223.255.255.255D224.0.0.0 - 239.255.255.255E240.0.0.0 - 255.255.255.2552. 保留IP范围
10.0.0.0 - 10.255.255.255
127.0.0.0 - 127.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
3. 子网范围计算
如：
1.1.1.101/28
/28表示前面28位的值为1，即 11111111 11111111 11111111 11110000
换算成10进制为 255.255.255.240
因此， /28 = 255.255.255.240 netmask
然后， 256 - 240 = 16, 即子网范围为16
1.1.1.0
1.1.1.16
1.1.1.32
… …
因此，1.1.1.101 位于 1.1.1.96 - 1.1.1.111
4. 子网掩码表
子网掩码位数子网掩码Hosts/31255.255.255.2541 host/30255.255.255.2522 hosts/29255.255.255.2486 hosts/28255.255.255.24014 hosts/27255.255.255.22430 hosts/26255.255.255.19262 hosts/25255.255.255.128126 hosts/24255.255.255.0254 hosts/23255.255.254.0510 hosts/22255.255.252.01022 hosts/21255.255.248.02046 hosts/20255.255.240.04094 hosts/19255.255.224.08190 hosts/18255.255.192.016382 hosts/17255.255.128.032766 hosts/16255.255.0.065534 hosts/15255.254.0.0131070 hosts/14255.252.0.0262142 hosts/13255.248.0.0524286 hosts/12255.240.0.01048574 hosts/11255.224.0.02097150 hosts/10255.192.0.04194302 hosts/9255.128.0.08388606 hosts/8255.0.0.016777214 hosts