Help with this 70-642 Question

vistalavista

This Q is on the MSPress book lesson 2 #3 question.

You are a network administrator for your company. You have recently deployed a server that runs Windows Server 2008 R2. The server is provided with the following IP configuration:
Address: 192.168.1.66
Subnet Mask: 255.255.255.224
Default Gateway: 192.168.1.1
Users on remote subnets complain that they are not able to access the new server.
Which of the following actions is most likely to resolve the problem?
A. Change the server address to 192.168.1.62
B. Change the server address to 192.168.1.34
C. Switch to a 26-bit subnet mask
D. Switch to a 25 bit subnet mask

Please explain how you arrive at your answer.

Thanks in advance.

crrussell3

In order to answer this question (yourself), try breaking down the question and the answers:

1. Take the given subnet mask. How many bit subnet mask is it? How many addresses are available in said subnet mask for clients? Does that range include the ip address of the server?
2. Does answer A fall within the range from step 1?
3. Does answer B fall within the range from step 2?
4. Convert the subnet mask into a 26 bit mask and determine the range. Does the ip address fall within said range?
5. Same as step 4 but with 25 bit mask. Does the ip address fall within said range?

By breaking it down, you can figure out the answer by applying the knowledge you should have picked up from this chapter/lesson.

MrAgent

Look at the question. It doesnt ask anything about which other subnets can not reach the IP. That right there eliminates 2 of the answers.

From there look at the IP and figure it out

vistalavista

MrAgent wrote: »

Look at the question. It doesnt ask anything about which other subnets can not reach the IP. That right there eliminates 2 of the answers.

From there look at the IP and figure it out

The answer given is D so it does in fact require to change the subnet ... which is why I was confused.

RobertKaucher

vistalavista wrote: »

You are a network administrator for your company. You have recently deployed a server that runs Windows Server 2008 R2. The server is provided with the following IP configuration:
Address: 192.168.1.66
Subnet Mask: 255.255.255.224
Default Gateway: 192.168.1.1
Users on remote subnets complain that they are not able to access the new server.
Which of the following actions is most likely to resolve the problem?
A. Change the server address to 192.168.1.62
B. Change the server address to 192.168.1.34
C. Switch to a 26-bit subnet mask
D. Switch to a 25 bit subnet mask

Please explain how you arrive at your answer.

Thanks in advance.

If we look at teh situation as it is with a 27 bit subnet mask the IP address 192.168.1.66 is NOT on the same sub-network as 192.168.1.1 therefore we must do one of 3 things to correct the issue:
1. Change the server's defaultgateway to a router on the same network.
2. Change the server's IP address so that it is on the same network as the router listed as the default gateway.
3. Change the subnetmask so that the server's IP address is on the same sub-network as 192.168.1.1.

So the question we have to ask is with a 27 bit netmask (255.255.255.224) is 192.168.1.1 on the same subnetwork as either answer A or B? No as the first range for 192.168.1.0/27 is 192.168.1.1-192.168.1.30 so we can exclude those right away. If we change the netmask to 255.255.255.192 (a 26 bit netmask) is 192.168.1.66 in the same subnetwork as 192.168.1.1? No as the first available range addresses for a 26 bit mask is 192.168.1.1-192.168.1.62. This leaves answer D. 255.255.255.128 (or a 25 bit netmask) has a first range of 192.168.1.1-192.168.1.126 so the server's IP address IS in that range. So that is the only possible answer.