question on subnet mask

Eh, I dredged this up from the depths... Almost makes we wish I never posted a tutorial--because now I have a bit "Tutorials:1" near my name and it just looks forlorn.

Now I’m confused.

If you take the tutorial from TERR and apply it, you have

IP1 10000000.00001000.10000001.00101011 (128.8.129.43)
IP2 10000000.00001000.10100001.00110111 (128.8.161.55)
mask 11111111 .11111111.00011111.00000000 (255.255.31.0 )


10000000.00001000.---00001.-------- (128.8.129.43)
10000000.00001000.---00001.-------- (128.8.161.55)

Couldn’t they be on the same network?? Is it possible??

well well well !!! computers are idiots .not WE!!!
coming to details of question, this question is being asked in GATE(graduate aptitude test in engineering) in india and there IS an answer to this one which i dunno.
i had worked on subnets problems like given IP address and 'n' systems in network etc etc.....
but this Q is not asked directly.
I think 'D' is correct answer. but i dont have solution!

Ahem, someone needs to go review RFCs... Netmasks MUST be continuous "1" bits.

Want to try prove me wrong?: Tell me the network and host addresses of 63.146.109.212 if it has a subnet mask of 255.255.31.0. Good luck.


Ammo

SolarWinds makes a nice subnet calculator. It's the one I use all the time although I am going to check out HTRegz's.

http://support.solarwinds.net/update...stomerFree.cfm

I would love to see someone give me an answer as to how N.N.31.x could be a legit subnetmask. Maybe this question was meant to leave blank since there is NO real answer??? ;)
Agreeing with ammo, the network side of the subnetmask has to be all '1' bits, and the host side of the subnetmask are all '0's.

And to go a little further into ammo's discussion, to show you proof that there is no such thing as a N.N.31.x subnetmask, look at RFC 1878