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Cheatography

IP Addressing Cheat Sheet by

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
Hx8 = 16
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 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.
               

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Comments

Thanks for building this cheat sheet for IP addressing. I have downloaded it to keep on hand.

Robert Bone- You are absolutely welcome! I created it to have handy for a GIAC exam. I'm glad it was useful for you as well.

Thank you Amanda for posting!

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