[ale] IP Calculations

[Joseph A Knapka]

Ken Nagorski wrote:
> 
> OK, there is something you need to know.
> 
> Is it classless or classful? if it is classful then
> 
> 0-127 is a class A ( first bit 0)
> 128-191 is in the clash B (first bits 10 )
> 192-223 class C ( fist bits 110 )
> 
> However mostly the world uses VLSM or CIDR, (classless) In this case you
> need to know how many bits are on for subnetting,
> 
> Lets say 24 (255.255.255.0) bits are on... Then you have 8 bits left for the
> network
> 
> You need to calculate 2^8 - 2 = 254 ( this is the amount of useable hosts )
> 
> The network will be the lowest IP ( before you minus 2 )
> The broadcast is the last IP in the block
> 
> Ken

Is it not true that a classess network may have any netmask
whatsoever? That is, you could have a netmask with lower-order
bits == 1 and higher-order bits == 0, like 255.255.255.4, or
something? I seem to remember encountering a network that
had such a netmask, but the details are hazy.

Cheers,

-- Joe

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