Subnet-zero does not mean any of the IP address octets must have all zeros
in them! It refers to that address space which falls outside the
traditional subnets.
>From: "Gareth Hinton" <[EMAIL PROTECTED]>
>Reply-To: "Gareth Hinton" <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Subject: Re: Ip addressing question
>Date: Thu, 25 Jan 2001 23:11:01 -0000
>
>But the third octet, would be 00000100, which is contained within the
>subnet
>portion of the address, so how can this be subnet zero.
>I agree that 192.16.4.0 with 255.255.255.252 would be a subnet zero,
>because
>the fourth octet would be 00000000 - 00000011 and only the 6 MSB's count.
>
>If I'm being thick you're going to have to ram it down my neck.
>I would like to make my excuses now, it's getting late in U.K.
>
>
>Gareth
>
>
>""Neil Schneider"" <[EMAIL PROTECTED]> wrote in message
>94qe36$vpl$[EMAIL PROTECTED]">news:94qe36$vpl$[EMAIL PROTECTED]...
> > yes 172.16.4.0 thru 172.16.4.3 would be subnet zero.
> >
> > Neil Schneider
> >
> >
> > ""Gareth Hinton"" <[EMAIL PROTECTED]> wrote in message
> > 94qd3r$s2r$[EMAIL PROTECTED]">news:94qd3r$s2r$[EMAIL PROTECTED]...
> > > I've read it five times and still can't see a subnet zero in the
>example.
> > > 172.16.x.x Class B address with a 255.255.255.252 subnet mask.
> > > Wouldn't subnet zero be down at 172.16.0.0 with 172.16.0.4 being the
>first
> > > 'non-subnet zero' address.
> > > 172.16.4.0 wouldn't be subnet zero would it?
> > >
> > > Gareth
> > >
> > > ""Frank Wells"" <[EMAIL PROTECTED]> wrote in message
> > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > > > Hey Jen,
> > > > Your understanding of subnetting is a little off and your teaching
>is
> > thus
> > > > tainted. Here is a how subnetting and subnet zero work:
> > > >
> > > > Take a IP address for example: 172. 16. 4. 0
> > > > Add an easy subnet mask to play with: 255.255.255.252
> > > >
> > > > What subnets to we get from this combo?...
> > > > First subnet= 172.16.4.4
> > > > Second subnet= 172.16.4.8
> > > > Third subnet= 172.16.4.12
> > > > ...
> > > > Last subnet= 172.16.4.252
> > > >
> > > >
> > > > Lets examine one of the subnets: 172.16.4.4
> > > > The IP address space this subnet consumes is 172.16.4.4 through
> > 172.16.4.7
> > > > The first and last IP addresses in the subnet range are the network
> > > address
> > > > and subnet broadcast address respectively, and neither the first or
>last
> > > > address can be used for host addressing, as is
> > > > well known. This leaves two remaining addresses available for hosts
>on
> > > that
> > > > subnet:
> > > >
> > > > 172.16.4.5 and 172.16.4.6
> > > >
> > > > Subnet zero is that address space which is not taken up by the
>subnets.
> > > In
> > > > our example this would be 172.16.4.1;172.16.4.2;172.16.4.3
> > > > Routers do not use subnet zero for anything unless instructed to do
>so
> > and
> > > > if this is the case, they will merely recognize it and route it.
>The
> > > > broadcast address in a subnet does not see the entire network, it
> > > broadcasts
> > > > only to its entire sub-network. Referring to our example once more,
> > this
> > > > would be the address 172.16.4.7 and only the two host addresses on
>the
> > > > subnet would hear a broadcast from it.
> > > >
> > > > Hope this clarifies things.
> > > >
> > > >
> > > >
> > > > >From: Jennifer Cribbs <[EMAIL PROTECTED]>
> > > > >Reply-To: Jennifer Cribbs <[EMAIL PROTECTED]>
> > > > >To: [EMAIL PROTECTED]
> > > > >Subject: RE: Ip addressing question
> > > > >Date: Thu, 25 Jan 2001 10:38:38 -0500
> > > > >
> > > > >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
> > > > >
> > > > >
> > > > >===== 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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> > > > >------------------------------------------------------------
> > > > >Have a Good Day!!
> > > > >Jennifer Cribbs
> > > > >[EMAIL PROTECTED]
> > > > >
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