The following test question appears in the "i-Net+ for Dummies" final exam section. I thought I new enough about subnet masks to answer the question but perhaps not. Either that or there is a typo in the answer section of the exam. I would like your input.

The question is:

Which of the following is most likely the subnet mask for 204.200.106.1?

The available answers are:

a) 255.0.0.0
b) 255.255.0.0
c) 255.255.255.1
d) 255.255.255.255

The answer key states:

D. 204.200.106.1 is obviously a Class C address, right? That means you would most likely use the default standard subnet mask for class C addresses.

I chose answer C.

Maybe I slept through an important part of subnet masks, so any help with this question would be appreciated.

Thanks!


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Rick

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Hmmm, "none of the above" wasn't a choice, huh? 255.255.255.000 is the default for a Class C address; 255.255.255.1 would be a router address.

I'm voting for 2 typos in the question.

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Typo in the book!!!

The correct subnet mask should be 255.255.255.0. It is Class C which reserves the first 24 bits. It is completely illegal to end a subnet in a .1. Subnets can only be: 128, 192, 224, 240, 248, 252 and 255

Hope this helps!

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San...
MCSE, MCDBA, MCT, i-Net+

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Thanks for the input. I had a sneaking suspicion that the error was typographical. The "i-Net+ Certification for Dummies" is a great reference but lacks some depth in many areas. All in all, this book together with the dumps available, plus Augie's flash cards (Thanks again Augie!)I think do a pretty good job. I will confirm this in a couple of weeks.

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Rick, good luck on your test! You are already following my #1 piece of advice -- Question everything! Don't just memorize the answers but make sure you understand the answer. Practically every source I used had at least one mistake.

AuroraB
i-Net+, CIW wannabe

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