Welcome to IP Addressing Cheat Sheet. An Internet Protocol address (IP address) is a numerical label such as 192.0.2.1 that is connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: network interface identification, and location addressing.
ADDRESS CLASS: A, B, C
| Class: | A | B | C |
| Range | 0-127 | 128-191 | 192-223 |
| N/H | N.H.H.H | N.N.H.H | N.N.N.H |
| Network Bits | Nx8 = 8 | Nx8 = 16 | Nx8 = 24 |
| Host Bits | Hx8 = 24 | W | Hx8 = 8 |
| # Addresses | 16,777,210 | 66,536 | 256 |
| Private Range | 10.0.0.0 – 10.255.255.255 | 172.16.0.0 – 172.31.255.255 | 192.168.0.0 – 192.168.255.255 |
| Subnet Mask | 255.0.0.0 | 255.255.0.0 | 255.255.255.0 |
ADDRESS CLASS: D & E
| CLASS | RANGE | NOTE |
| D | 224 – 239 | reserved for multicasting |
| E | 240 – 255 | reserved for research & development |
Power of 2 table
| 2^0 | 1 | 2^8 | 256 |
| 2^1 | 2 | 2^9 | 512 |
| 2^2 | 4 | 2^10 | 1,024 |
| 2^3 | 8 | 2^11 | 2,048 |
| 2^4 | 16 | 2^12 | 4,096 |
| 2^5 | 32 | 2^13 | 8,192 |
| 2^6 | 64 | 2^14 | 16,384 |
| 2^7 | 128 | 2^15 | 32,768 |
BIT, VALUE, MASK
| BIT | VALUE | N-BITS / H-BITS | MASK |
| 1 | 128 | 1 / 7 | 10000000 |
| 2 | 192 | 2 / 6 | 11000000 |
| 3 | 224 | 3 / 6 | 11100000 |
| 4 | 240 | 4 / 4 | 11110000 |
| 5 | 248 | 5 / 3 | 11111000 |
| 6 | 252 | 6 / 2 | 11111100 |
| 7 | 254 | 7 / 1 | 11111110 |
| 8 | 255 | 8 / 0 | 11111111 |
SOME FORMULAS
| # BLOCKS FOR LARGE #s | 2^H / 256 = # BLOCKS |
| NUMBER OF SUBNETS = | 2^n ( n = Number of borrowed bits from the host) |
| NUMBER HOSTS PER SUBNET = | (2^h – 2) ( h = Number of Host bits) |
Hosts have always been with the “-2” part. Because the network address and broadcast address have always been unusable for hosts.
IP Addressing Cheat Sheet
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