>Subnet zero is the network address that the routers uses for routing to the
>network and the broadcast address sends a broadcast to the entire network
>everytime it is used, which means it goes to all subnets. Therefore, these
>are not used as host addresses. They encompass the whole network. Others can
>probably add to this.
>
>Jennifer Cribbs
The restrictions on subnet zero and the all ones subnet are a
limitation of classful routing protocols, which do not transmit a
subnet mask. Without a subnet mask, what is the difference between:
10.0.0.0 (the network)
10.0.0.0 (subnet 0.0.0. of network 10)
But there's no ambiguity in what a classless protocol sends:
10.0.0.0/8
10.0.0.0/16
So there's a clear problem with subnet zero in a classful
environment. Restrictions on the all-ones subnet have never made as
much sense, other than the conceptual ambiguity being the broadcast
to:
all subnets of 10.0.0.0/8 10.255.255.255
broadcast to 10.255.255.0/24 10.255.255.255
I've never seen the all-ones subnet actually cause problems, even
with classful routing.
>
>
>===== Original Message From "Fred Danson" <[EMAIL PROTECTED]> =====
>> Could anyone explain to me why Subnet zero and the last subnet are not
>>normally used?? I see why 2 host addresses are reserved in every subnet
>>(network address and broadcast address), but I never understood why 2
>>networks are not used. What is the difference between these networks and the
>>networks in between?
>>
>>Thanks in advance,
>>
> >Freddy
> >
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