Intro exam - Question

Unanswered Question
Mar 22nd, 2007


m new to Networking, studying for the intro exam and have a quick question im hoping someone can help me with.

When Calculating the number of subnets do you sbtract 2?

e.g Using 6 subnet bits are 62 or 64 subnets created?


I have this problem too.
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Brandon Buffin Thu, 03/22/2007 - 13:00

It depends. The purpose of subtracting 2 is to exclude the all 0s and all 1s subnets. Prior to IOS 12.0 you could not use these subnets by defualt. You could however, use the command "ip subnet-zero" to allow their use. As of IOS 12.0, "ip subnet-zero" is enabled by default. So, if you're using "ip subnet-zero" you would not subtract 2. If you are not using "ip subnet-zero", you would subtract 2. Take a look at the following link.

Hope this helps. If so, please rate the post.



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