Project2501 wrote:daver1982 wrote:so basically i cant:

find host number for IP,

dave

I work out the number of IP addresses by building up to the point were the subnet mask starts.

If you're subnet mask is 255.255.255.0 then how many IP addresses are in the last portion? 256

If you're subnet mask is 255.255.254.0 then how many IP addresses are in the last portion? 512

If you can work out how I got those numbers you're on the right track.

ok, from looking at the pdf link i have come up with the following patterns and conclusions.

from 255 to 0 there are 8 parts which i guess are the bits ? 255 counts down binary, so -1 -2 -4 etc until - 128 to = .0 .

so if there is 8 parts to each part of the ip address then there are 32 levels of binary = total ammount of ip's possible?

so trying to explain where i am with this in my working out, if the subnet mask is 255.252.0.0 , there would be 18 levels of binary to = the amount of ip addresses. so in basic maths, 1*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2=262144.

i know i have the answers on the pdf, i just want to get it straight in a way i can understand!