What does the "/24" mean? How does that relate to my subnet mask?
InterMapper uses the Classless Inter-Domain Routing (CIDR) notation to represent IP subnet information. The number in the "/xx" shorthand stands for the number of bits set to one in the subnet mask. The convention is always to start at the left end of the 32-bit subnet mask. The table below shows the correspondence between the "/xx" notation and the actual numeric representation.
| Code: |
Subnet Mask # of Addresses Subnet Mask # of Addresses
/1 128.0.0.0 2.1 billion /17 255.255.128.0 32,766
/2 192.0.0.0 1 billion /18 255.255.192.0 16,382
/3 224.0.0.0 536 million /19 255.255.224.0 8,190
/4 240.0.0.0 268 million /20 255.255.240.0 4,094
/5 248.0.0.0 134 million /21 255.255.248.0 2,046
/6 252.0.0.0 67 million /22 255.255.252.0 1,022
/7 254.0.0.0 34 million /23 255.255.254.0 510
/8 255.0.0.0 17 million (Class A) /24 255.255.255.0 254 (Class C)
/9 255.128.0.0 8.4 million /25 255.255.255.128 126
/10 255.192.0.0 4.2 million /26 255.255.255.192 62
/11 255.224.0.0 2.1 million /27 255.255.255.224 30
/12 255.240.0.0 1 million /28 255.255.255.240 14
/13 255.248.0.0 524 thousand /29 255.255.255.248 6
/14 255.252.0.0 262 thousand /30 255.255.255.252 2
/15 255.254.0.0 131 thousand /31 255.255.255.254 RFC 3021
/16 255.255.0.0 65,534 (Class B) /32 255.255.255.255 A single address |
