常用子网掩码换算对照表

1.掩码255.0.0.0/8(A类地址默认掩码)
2.掩码255.128.0.0/9
3.掩码255.192.0.0/10
4.掩码255.224.0.0/11
5.掩码255.240.0.0/12
6.掩码255.248.0.0/13

7.掩码255.252.0.0/14
8.掩码255.254.0.0/15
9.掩码255.255.0.0/16(B类地址默认掩码)
10.掩码255.255.128.0/17
11.掩码255.255.192.0/18
12.掩码255.255.224.0/19
13.掩码255.255.240.0/20
14.掩码255.255.248.0/21
15.掩码255.255.252.0/22
16.掩码255.255.254.0/23
17.掩码255.255.255.0/24(C类地址默认掩码)
18.掩码255.255.255.128/25
19.掩码255.255.255.192/26
20.掩码255.255.255.224/27
21.掩码255.255.255.240/28
22.掩码255.255.255.248/29
23.掩码255.255.255.252/30