netmask                 aggregate       addresses       wild bits
=====================================================================
255.0.0.0               /8              16777216       0.255.255.255
255.128.0.0             /9              8388608        0.128.255.255
255.192.0.0             /10             4194304         0.63.255.255
255.224.0.0             /11             2097152         0.31.255.255
255.240.0.0             /12             1048576         0.15.255.255
255.248.0.0             /13             524288          0.7.255.255
255.252.0.0             /14             262144          0.3.255.255
255.254.0.0             /15             131072          0.1.255.255
255.255.0.0             /16             65636           0.0.255.255
255.255.128.0           /17             32768           0.0.127.255
255.255.192.0           /18             16384           0.0.63.255
255.255.224.0           /19             8192            0.0.31.255
255.255.240.0           /20             4096            0.0.15.255
255.255.248.0           /21             2048            0.0.7.255
255.255.252.0           /22             1024            0.0.3.255
255.255.254.0           /23             512             0.0.1.255
255.255.255.0           /24             256             0.0.0.255
255.255.255.128         /25             128             0.0.0.127
255.255.255.192         /26             64              0.0.0.63
255.255.255.224         /27             32              0.0.0.31
255.255.255.240         /28             16              0.0.0.15
255.255.255.248         /29             8               0.0.0.7
255.255.255.252         /30             4               0.0.0.3
255.255.255.254         /31             2               0.0.0.1
255.255.255.255         /32             1               0.0.0.0