Netmask                 Binary                                  CIDR    Notes

        255.255.255.255         11111111.11111111.11111111.11111111     /32     1   useable
        255.255.255.254         11111111.11111111.11111111.11111110     /31     0   useable
        255.255.255.252         11111111.11111111.11111111.11111100     /30     2   useable
        255.255.255.248         11111111.11111111.11111111.11111000     /29     6   useable
        255.255.255.240         11111111.11111111.11111111.11110000     /28     14  useable
        255.255.255.224         11111111.11111111.11111111.11100000     /27     30  useable
        255.255.255.192         11111111.11111111.11111111.11000000     /26     62  useable
        255.255.255.128         11111111.11111111.11111111.10000000     /25     126 useable

        255.255.255.0           11111111.11111111.11111111.00000000     /24     class C

        255.255.254.0           11111111.11111111.11111110.00000000     /23     2   class C's
        255.255.252.0           11111111.11111111.11111100.00000000     /22     4   class C's
        255.255.248.0           11111111.11111111.11111000.00000000     /21     8   class C's
        255.255.240.0           11111111.11111111.11110000.00000000     /20     16  class C's
        255.255.224.0           11111111.11111111.11100000.00000000     /19     32  class C's
        255.255.192.0           11111111.11111111.11000000.00000000     /18     64  class C's
        255.255.128.0           11111111.11111111.10000000.00000000     /17     128 class C's
        
        255.255.0.0             11111111.11111111.00000000.00000000     /16     class B

        255.254.0.0             11111111.11111110.00000000.00000000     /15     2   class B's
        255.252.0.0             11111111.11111100.00000000.00000000     /14     4   class B's
        255.248.0.0             11111111.11111000.00000000.00000000     /13     8   class B's
        255.240.0.0             11111111.11110000.00000000.00000000     /12     16  class B's
        255.224.0.0             11111111.11100000.00000000.00000000     /11     32  class B's
        255.192.0.0             11111111.11000000.00000000.00000000     /10     64  class B's
        255.128.0.0             11111111.10000000.00000000.00000000     /9      128 class B's

        255.0.0.0               11111111.00000000.00000000.00000000     /8      class A

        254.0.0.0               11111110.00000000.00000000.00000000     /7      2   class A's
        252.0.0.0               11111100.00000000.00000000.00000000     /6      4   class A's
        248.0.0.0               11111000.00000000.00000000.00000000     /5      8   class A's
        240.0.0.0               11110000.00000000.00000000.00000000     /4      16  class A's
        224.0.0.0               11100000.00000000.00000000.00000000     /3      32  class A's
        192.0.0.0               11000000.00000000.00000000.00000000     /2      64  class A's
        128.0.0.0               10000000.00000000.00000000.00000000     /1      128 class A's

        0.0.0.0                 00000000.00000000.00000000.00000000     /0