Subnetting question...

binaryhat

Question: Which subnet does host 172.25.202.3 255.255.255.240 belong to?

Block size is 16, 256-240
3rd octet

0
16
32
48
64
80
96
112
128
144
160
176
192
208

Answer: 172.25.202.0

It should be 172.25.192.0, yes?

blatini

It's fourth octet. First through third are already maxed at 255. So it would be 172.25.202.0 network with 172.25.202.15 broadcast.

binaryhat

Ahhh...mental block. I see now.

NetworkVeteran

Good explanation, blatini.

Ollie1211

Hi I'm not sure if this is where I post this but, I have an example question for an exam, and I was hoping someone could explain the answer to me. If the ip address on my machine is 192.168.1.73 and the subnet mask is 255.255.255.192, which of the following devices are also on my IP subnet?
i. 192.168.1.64
ii. 192.168.1.65
iii. 192.168.1.63
iv. 192.168.1.73
are they all on my IP subnet seen as the first 3 octets are the same. I'm just confused with this. Thanks for any help.

blatini

Is that a real question? Why would the original host also be a part of the question? I suppose the answer is ii and iv. You are looking at the fourth octet and have 2 subnet bits and 6 host bits. 192.168.1.0, 192.168.1.64, 192.168.1.128.... etc.

Only reason I ask if it's real is because there's a chance you mistyped and the answer could actually be completely different... not trying to be condescending or anything.

Ollie1211

Sorry about that, it should of been for iv. 192.168.1.173

alphagolf

IP:192.168.1.73
Mask: 255.255.255.192

Meaning you've got a 64 block in the 4th octet.

Subnets as blatini pointed out are as follows:
192.168.1.0
192.168.1.64
192.168.1.128
etc.

If you're not sure why we're counting up in 64's you may want to visit some of the other subnetting topics. I learnt how to subnet from this thread in particular: http://www.techexams.net/forums/ccna-ccent/38772-subnetting-made-easy.html

Your device of 192.168.1.73 is in between the x.64 x.128 subnets.

So, as blatini mentioned your answers are x.65 and x.63.

192.168.1.64 is NOT included because it's the subnet ID and is not associated with an actual device.

HTH