Subnet question

[vincemcmahon]

The network 172.25.0.0 has been subnetted to accommodate 5 subnets.
Which of the following IP addresses could be assigned to a host in the
third subnet if the no ip subnet zero command configured on the router?

E. 172.25.96.1
F. 172.25.118.194

which answer is correct? only 1 answer is correct but it seems to be
that both are correct, as my logic is follows:

the subnet is 255.255.224.0 and 32 is each segment number

32.0 64.0 96.0 128.0 ........

96.0 is the third subnet

so both anwser E and F can be the host IP, isn't it?!

Thanks

 

[Cluebird]

Looks like a misprint with F. "They" probably meant 172.25.128.194. Your reasoning is flawless and correct. Both addresses are legal host addresses on the third usable subnet as written.

 

[Microbyte]

or misprint can be in E. If E selection is 172.25.96.0 then F is the correct answer, because such address isn't a host.
if misprint is on F like what Cluebird wrote then E is the correct answer.

anyway, it seems like you know your subnetting. conquer that test!!!


Microbyte

 

[vincemcmahon]

Thanks, I also agree with you two.

As a matter of fact, I.......passed the 801 exam yesterday! ^^

 

[Microbyte]

congrat vince!


Microbyte

 

[vincemcmahon]

thanks, next i will move on ccsa and ccse

 

[DeFreitasM]

Vince,
The correct answer should be F!

Subnet Zero should be considered invalid on any vendor 's Cert. Exam....

Just my 2 cent

M

 

[Cluebird]

Subnet zero is not considered invalid on any vendor's exam. Subnet zero is valid and now considered a default setting for Cisco devices as networking moves from classful to classless with VLSM and CIDR/summarization/aggregation. Questions on Cisco exams test whether a delegate understands the implications of subnet zero and are written explicitly to allow or deny use of subnet zero. They also clearly state either a requisite number of usable hosts or subnets as design criteria to check understanding of what is usable and what is not.

Unfortunately, many of the test prep quizzes aren't quite as exact.

I'm not clear why you state F is the only answer? Both E (172.25.96.1/19) and F (172.25.118.194/19) are on the same subnet (172.25.96.0/19-172.25.127.255/19) and are valid host addresses. With the /19 prefix, there are 8 new subnets created (6 usable unless subnet-zero is allowed) with each subnet having 2^13 hosts (minus 2).

 

[jtb]

maybe they want x.x.x.1 for the rtr interface?

JTB
Senior Microsoft Consultant
MCSE-NT4+W2K, MCP+I, MCP-W2K, CCNA,
CCDA, CTE, MCIWD, i-Net+, Network+
(CCNP, MCSA/MCSE-2K3 in progress)

 

[bierhunter]

But the router interface is still considered a host address in the subnet. Since the question didn't specify, it leaves the entire subnet available for use (except for network and broadcast addresses of course).

E and F are both valid, so I agree, one's a misprint.