Re: Localtalk gateway/bridge

[dempson@actrix.gen.nz (David Empson)]

william strutts <wrstrutts1@nospam.home.com> wrote:

> "David Empson" <dempson@actrix.gen.nz> wrote in message
> 1ezjmb9.6u7z8l18zjadcN%dempson@actrix.gen.nz">news:1ezjmb9.6u7z8l18zjadcN%dempson@actrix.gen.nz...
> 
> > The "for private use" address ranges are:
> >
> > Class A: 10.0.0.0 through 10.255.255.255 (one network with 16 million
> > addresses, or smaller subnets as appropriate).
> >
> > Class B: 172.16.0.0 through 172.31.255.255 (16 networks with 65536
> > addresses each, or larger or smaller subnets as appropriate).
> 
> Are you positive about this one. I checked my Mac ethernet adapter
> software and it says Class B is 128.0.0.0.

I was referring to the specific subrange of class B addresses which are
reserved for private use and are not routable over the public Internet
(as are 10.* and 192.168.*).

> > In each case, the "all zeros" and "all ones" addresses within the
> > network are reserved.
> 
> I had read you only 254 per class.  For instance, 10.0.0.1 to 10.0.0.254
> was the only possible range.

In the case of the 10.* address range, assuming you used a subnet mask
of 255.0.0.0, you could use addresses 10.0.0.1 through 10.255.255.254 (a
total of 16777214 stations on your network).  The special addresses
10.0.0.0 (the entire subnet) and 10.255.255.255 (subnet broadcast) are
reserved and cannot be used for station addresses.

The same rule applies when you break your address range up into smaller
subnets: the first and last address in the subnet are reserved.

Consider a class C address range, such as 192.168.1.0 through
192.168.1.255.  In this case, the default subnet mask is 255.255.255.0,
giving you 256 addresses, of which 254 are usable.  Using the standard
notation, this network and subnet mask would be 192.168.1.0/24.

If you have a router, you can break this address range into smaller
subnets, which may be convenient for physical reasons.

For example, you could split the address range in half, using a subnet
mask of 255.255.255.128, giving you two subnets: 192.168.1.0/25 and
192.168.1.128/25.  Each subnet has two reserved addresses, leaving 126
available for stations, or a total of 252 stations spread over all
subnets.

At the other extreme, you could set up 64 subnets each containing four
addresses, of which two are reserved.  The networks would be addressed
as 192.168.1.0/30, 192.168.1.4/30, ..., 192.168.1.252/30.  In this case,
you have wasted half your available addresses, leaving you with 128
usable addresses (two in each subnet) spread over all subnets.