This is the way that I do subnetting in my head to impress my nerd friends.
But I could never explain how it worked. Thanks for putting that into
words..
-Ejay
-----Original Message-----
From: Tony Medeiros [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, July 11, 2001 12:06 PM
To: [EMAIL PROTECTED]
Subject: Re: calculating allowable hosts [7:11902]
Paul,
There are many ways to do this. I'll show you my technique that is fast and
works good.
First, Take the number in the right most octet that isn't 255 and subtract
it from 256. In your case it's 248. This gives you 8.
Now, 8 is the number that the subnets increment. The first subnet is zero,
then 8, then 16, then 24, etc.
Now, take the number in you last octet and divide it by 8. In your case
it's 184 divided by 8 with equals a nice round 23. Because there are no
remainders in you division, that means you are given a valid network number,
not a host number on that network.
Now, Because of your mask we know the networks increment by 8. So your
network is 213.13.184.184. The next network is 213.13.184.172. Your hosts
are the numbers in between. BUT...
Always remember your network number is the network identifier and can't be
used for a host. And, the last number in your network is the broadcast
address for your subnet.
So, The network is 213.13.184.184 (can't use this for a host), The host
address are 213.13.184.185, 186, 187, 188, 189, 170. The broadcast address
is 213.13.184.171. and the number of the next subnet is 213.13.184.172.
Remember that you always loose 2 address for each subnet: one for the
network number and one for the broadcast. A nice rule of thumb is that if
the networks increment by 4, you have 2 usable host addresses. By 8, 6
usable addresses. By 16, 14 usable address, etc
If this still confuses you, write it out in binary. If you learn it in
binary, you've learned it !!
Tony M.
#6172
----- Original Message -----
From: paul
To:
Sent: Wednesday, July 11, 2001 3:11 AM
Subject: calculating allowable hosts [7:11902]
> Greetz,
> Can anyone explain how you get the allowable host addresses from the
> following 213.13.184.184 with 255.255.255.248?(or show where I can figure
> this out )
> Thanx
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=11972&t=11902
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