subnetting practice

Answered Question
Sep 19th, 2007

Hello everyone,

I have started studying for the ccna and am in a training class. I understand most of what is taught for subnetting, but if I am going to complete problems in a minute or so I need lots of practice.

Is there any kind of "workbook" that gives clear explainations and lots of practice problems that anyone could recommend?

Thanks much,


I have this problem too.
0 votes
Correct Answer by akimalijbsk8r about 9 years 1 month ago

Also, you may want to try this free site that I found. Repetitive but lots of questions.

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Overall Rating: 4.3 (6 ratings)
cyphur353 Thu, 09/20/2007 - 03:31

The CCNA Prep Center has some online games which help you drill on binary to decimal conversion, as well as subnetting practice. Check into it.

kareem.afifi Mon, 10/08/2007 - 08:11

was listed above is great. I highly recommend it.

Maureen99 Sat, 09/22/2007 - 14:16

Thanks all for the resources. I haven't gotten to them all yet but the one's I have are very helpful.

Again, the help is greatly appreciated!


keesjan.schilstra Wed, 09/26/2007 - 13:28

I might have a solotion for you and others in finding more time during the exam.

Subnetting should cost you 10 sec a question there are some 10 questions about subnetting so that would not cost you more then 2 minutes. Subnetting in 10 seconds?

Yes its simple.

Write down the bitnumbers of the last 2 octets and the sequence of 128 64 etc.




for example give me the subnet and broadcastadress of

it's simple look at the table 22 is step 4

Divide 61 by step 4 and multiply the WHOLE NUMBER 15 by step 4 the subnet is 60 next subnet is 60 plus step 4 = 64 so broadcastadress is 63.255 (B-class)

61/4=15*4=60 next subnet 64 so subnet is 63.255

or look at the table. 19 is step 32

61/32=1*32 subnet= 32 next subnet is 32+32=64 so broadcast is 63.255

or /28

15/16=0 0*16=0 so subnet is 0 next subnet is 16 broadcast is 15 (C- class)


keesjan.schilstra Mon, 11/05/2007 - 22:21


I disagree, much to complex to use during an exam.

With my method you can subnet in 3 seconds and the awnser is allways right. And if you have 10 subnetting questions in an exam you can do them fast. In this way you create time for all the other questions.

Next time if you post something use the words "Maybe this is a solution, instead of "THIS IS A BETTER.....

mufandi102772 Tue, 11/06/2007 - 21:45


The CCNA certification Guides for both the Intro and ICND by Wendell Odom shows you simple ways to do subnetting. It was very helpful. I have been doing subnetting for a long time and it's easy to get lost if you don't use it that often. I found the chart they use very simple to use and once you master the concepts, you can tackle a lot of subnet problems...It's not exhaustive but it's really good. You need that when you go to take the exam because the time is just not enough...there may be simpler tools out there, but I doubt. This will help you from having to memorize..

Good Luck



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