Question from Sybex book

Everlife

Hi guys,

I ran into a question in the Sybex book I'm having some trouble with. I had always felt I had a somewhat decent understanding of subnetting, but this question has stumped me. My guess is I'm missing something obvious, but for the life of me I just can't figure it out...

A computer on your network is unable to communicate with other computers on the network. Below is the configuration:

IP Address: 134.62.2.55
Subnet Mask: 255.255.192.0
Default Gateway: 134.62.89.1

Which of the following settings is the cause of the problem?

A. IP Address
B. Subnet Mask
C. Default Gateway
D. None of the above. The problem must lie elsewhere

Answer: A. The IP address for the workstation is illegal given the subnet mask.

To my knowledge, the subnet ranges for this subnet mask would be:

134.62.0.0 - 134.62.63.255
134.62.64.0 - 134.62.127.255
134.62.128.0 - 134.63.191.255
134.62.192.0 - 134.63.255.255

Why would the IP be illegal with that subnet mask? It's been a while since I've done any serious subnetting. =/

Thanks for the help!

motherwolf

Your IP ranges are correct but have a look at the address of the PC and then look at the address of the default gateway. They're on different subnets. You'll have to either put the PC on the default gateway's subnet or configure a different DG that is within the PC's subnet. Hope that's not to confusing.

Everlife

Makes sense Mother, that's what I thought. What confused me was their wording on why it was incorrect. Thanks for the clarification!

hannos

I also was confused as to their answer.

I chose Default Gateway as being wrong (it is) but Sybex said the IP was wrong.

From what I can gather, there's actually 2 correct answers?

EDIT:

The questions says the PC is unable to communicate with others on the Network, not subnet. This would almost certainly indicate an incorrect default gateway?

dynamik

Is there a diagram or more to the question?

hannos

In your network, a workstation has the IP settings shown in the following table. This computer is unable to communicate with any other computers on the network.

ip 134.62.2.55
mask 255.255.192.0
gateway 134.62.89.1


Which of the following settings is the cause of this problem?

A. IP address
B. subnet mask
C. default gateway
D. none of the above







Now that I've really re-read the question is does state "any" other computers. This would signify there are no computers in the IP address range that it is in, therefore, it's IP address is wrong (as Sybex states). Thus, my answer of Default Gateway is incorrect.


I do not agree the IP is illegal, just wrong.

I must learn to READ the questions!

sprkymrk

hannos wrote:

Now that I've really re-read the question is does state "any" other computers. This would signify there are no computers in the IP address range that it is in, therefore, it's IP address is wrong (as Sybex states). Thus, my answer of Default Gateway is incorrect.

Yes, exactly.

When they say "other computers on the network" they generally are talking about the same subnet, or the LAN in general. If it said it could not communicate with computers on other subnets, or it had no Internet access, then you would assume the gateway is wrong.

Definately a tricky question.