IP Addressing

benford266

Hi Guys

Long time reader first time poster.

Just going through some practice questions before i go for my exam and i have come across this question. Please any explain to me where i have gone wrong. I picked answers a and b because the default subnet would be a 255.0.0.0 for a class a address. The correct answer for the question is d and f.

At a guess would it be because they need to be in a different subnet to 10.0.0.0 because they are on different interfaces of the router?

PC1 and PC2 are on two different Ethernet LANs that are separated by an IP router. PC1’s IP
address is 10.1.1.1, and no subnetting is used. Which of the following addresses could be used
for PC2? (Choose two answers.)
a. 10.1.1.2
b. 10.2.2.2
c. 10.200.200.1
d. 9.1.1.1
e. 225.1.1.1
f. 1.1.1.1

Thanks in advance
Ben

Priston

PC1 connects to R1
PC2 connects to R1

Since routers create broadcast domains, like you said, they need to be on different networks
A is on the same network as 10.1.1.1
B is on the same network as 10.1.1.1
C is on the same network as 10.1.1.1
D is on a different network
E is a Class D network (multicast)
F is on a different network

If both PCs connected to a switch they could be on the same network

http://images.ientrymail.com/networknewz/030104figure2.gif

benford266

Thanks, I took my best guess at it since i have never added a ip address to a router interface without a subnet mask.

Thinking about it now it makes sense since they cannot be on the same subnet.

Simrid

I remember I got stuck on this question to - I can't remember the reasoning behind (sorry to be useless) but it's an odd question.

satishtech

Yes answers d and f are correct...

Answers a to c - same class subnet 10.0.0.0/8
Answer e ,cannot use 255 as it is meant for broadcast.

ccie14023

Actually, there is no reason PC2 couldn't "use" 225.1.1.1, since it might very well be a multicast receiver. Obviously the implication of the question is which unicast addresses are valid, but having been an exam question writer before, I was taught to be totally explicit. Not that many vendors observe good question writing technique...

benford266

Thanks guys.

Iv learnt from this mistake i need to start putting more time into each question instead of trying to rush through it.