To supplement the courses in our Cyber Security ​Career Development Platform, here is our IPv4 Subnet Cheat Sheet.Â
You may download the PDF version of this cheat sheet here.
Subnets
| CIDR | SUBNET MASK | OF ADDRESSES | WILDCARD |
|---|---|---|---|
| /32 | 255.255.255.255 | 1 | 0.0.0.0 |
| /31 | 255.255.255.254 | 2 | 0.0.0.1 |
| /30 | 255.255.255.252 | 4 | 0.0.0.3 |
| /29 | 255.255.255.248 | 8 | 0.0.0.7 |
| /28 | 255.255.255.240 | 16 | 0.0.0.15 |
| /27 | 255.255.255.224 | 32 | 0.0.0.31 |
| /26 | 255.255.255.192 | 64 | 0.0.0.63 |
| /25 | 255.255.255.128 | 128 | 0.0.0.127 |
| /24 | 255.255.255.0 | 256 | 0.0.0.255 |
| /23 | 255.255.254.0 | 512 | 0.0.1.255 |
| /22 | 255.255.252.0 | 1024 | 0.0.3.255 |
| /21 | 255.255.248.0 | 2,048 | 0.0.7.255 |
| /20 | 255.255.240.0 | 4,096 | 0.0.15.255 |
| /19 | 255.255.224.0 | 8,192 | 0.0.31.255 |
| /18 | 255.255.192.0 | 16,384 | 0.0.63.255 |
| /17 | 255.255.128.0 | 32,768 | 0.0.127.255 |
| /16 | 255.255.0.0 | 65,536 | 0.0.255.255 |
| /15 | 255.254.0.0 | 131,072 | 0.1.255.255 |
| /14 | 255.252.0.0 | 262,144 | 0.3.255.255 |
| /13 | 255.248.0.0 | 524,288 | 0.7.255.255 |
| /12 | 255.240.0.0 | 1,048,576 | 0.15.255.255 |
| /11 | 255.224.0.0 | 2,097,152 | 0.31.255.255 |
| /10 | 255.192.0.0 | 4,194,304 | 0.63.255.255 |
| /9 | 255.128.0.0 | 8,388,608 | 0.127.255.255 |
| /8 | 255.0.0.0 | 16,777,216 | 0.255.255.255 |
| /7 | 254.0.0.0 | 33,554,432 | 1.255.255.255 |
| /6 | 252.0.0.0 | 67,108,864 | 3.255.255.255 |
| /5 | 248.0.0.0 | 134,217,728 | 7.255.255.255 |
| /4 | 240.0.0.0 | 268,435,456 | 15.255.255.255 |
| /3 | 224.0.0.0 | 536,870,912 | 31.255.255.255 |
| /2 | 192.0.0.0 | 1,073,741,824 | 63.255.255.255 |
| /1 | 128.0.0.0 | 2,147,483,648 | 127.255.255.255 |
| /0 | 0.0.0.0 | 4,294,967,296 | 255.255.255.255 |
Decimal to Binary
| SUBNET MASK | WILDCARD |
|---|---|
| 255 1111 1111 | 0 0000 0000 |
| 254 1111 1110 | 1 0000 0001 |
| 252 1111 1100 | 3 0000 0011 |
| 248 1111 1000 | 7 0000 0111 |
| 240 1111 0000 | 15 0000 1111 |
| 224 1110 0000 | 31 0001 1111 |
| 192 1100 0000 | 63 0011 1111 |
| 128 1000 0000 | 127 0111 1111 |
| 0 0000 0000 | 255 1111 1111 |
Binary to Decimal
IP Address Classes
| A | 0.0.0.0 – 127.255.255.255 |
| B | 128.0.0.0 – 191.255.255.255 |
| C | 192.0.0.0 – 223.255.255.255 |
| D | 224.0.0.0 – 239.255.255.255 |
| E | 240.0.0.0 – 255.255.255.255 |
Reserved (Private) Ranges
| CLASS A | 10.0.0.0 – 10.255.255.255 |
| CLASS B | 172.16.0.0 – 172.31.255.255 |
| CLASS C | 192.168.0.0 – 192.168.255.255 |
| LOCALHOST | 127.0.0.0 – 127.255.255.255 |
| ZEROCONF (APIPA/BONJOUR) | 169.254.0.0 – 169.254.255.255 |
Terminology
| WILDCARD MASK | A wildcard mask indicates which parts of an IP address are available for examination. |
| CIDR | Classless interdomain routing was developed to provide more granularity than legacy classful addressing; CIDR notation is expressed as /XX |
Thank you!
You should add RFC 1918 address space to this list
Thank you Sir.
Thank you!
this is very useful.
Thank you for sharing useful resources !
These subnetting masks are really useful for IPv4 addresses.
Thank you.
Love this – thank you!
Thank you very much Nathan. Appreciate that.
My pleasure.
Thank you! This is a very useful cheatsheet.