# Helpful tip on how to Remember the IP Range Classes

Member Posts: 13 ■□□□□□□□□□
I hope this helps some people like it helped me in for remembering the classed of IP’s

First thing take the highest IP range you can possibly possess which is 255

The only number you have to remember is 16 (2 bytes) Whatever works for you but 16 is the magic number.

So how does this work.

NOTE: I did this in MS word so the red column refers to the Far Right numbers (Your right, NOT the screen right) and the blue column refers to the number in middle column.

Take 255 and subtract 16 which equal 239

Now with just these two columns you would add all the red numbers in the column to get you following subtraction number in this case since there is only one number in the red column then it would just be (16 + 0 = 16)

E

255

16

D

239

C

B

A

So this is how you would get your next number to subtract from, so now subtract 239 – 16 = 223
No you follow the same routine as before so not you would add everything in your red column to get your next subtraction number which would be (16 + 16 = 32)

E

255

16

D

239

16

C

223

B

A

Now you take 223 -32 which equals 191

E

255

16

D

239

16

C

223

32

B

191

A

Once again you do the exact same process and add the entire red column to get your following subtraction number which in this case would be (16 + 16 + 32 = 64)

E

255

16

D

239

16

C

223

32

B

191

64

A

Now 191 - 64 = 127

E

255

16

D

239

16

C

223

32

B

191

64

A

127

Now that you have all of your ending IP ranges for each IP class. Just fill in the beginning IP ranges ensuring that no two number conflict.
Therefore Class A would be from 1 to 127
Class B would be 128 (since 127 is in class A ) to 191
Class C would be 192 (since 191 is in class to 223 and ect… until you come up with this

E

240

255

16

D

224

239

16

C

192

223

32

B

128

191

64

A

0

127

But this is the easiest way I found to remember the Classes of IP ranges for any certification test.