Nice conversation you've been listening to! If it would be impossible to
route a class C address over the internet than we would neither be able
to read eachothers e-mail nor to surf the www, since many ISPs give to
their clients IP-addresses out of a pool of a class C net.
You can find the correct definition in some RFC's but this will give you
an overview:
Class A means that the first digits of an IP-adress determins the
network address: nnn.xxx.xxx.xxx. So you can have 254 different networks
(255 and 0 excl.) with up to 255*255*254 workstations. (I think the
definition of class A is not really correct. I think more than the 254
and 0 are reserved but I've forgotten that)
Class B means that the first 2 digits of an IP-adress determins the
network address: nnn.nnn.xxx.xxx. So you can have 254*255 different
networks (255 and 0 excl. in the first digit) with up to 254*254
workstations.
Class C means that the first 3 digits of an IP-adress determins the
network address: nnn.nnn.nnn.xxx. So you can have 254*255*255 different
networks (255 and 0 excl.) with up to 254 workstations.
There are some sets of addresses that are treated as local ones:
>From RFC 1597:
>
>3. Private Address Space
>
> The Internet Assigned Numbers Authority (IANA) has reserved the
> following three blocks of the IP address space for private networks:
>
> 10.0.0.0 - 10.255.255.255
> 172.16.0.0 - 172.31.255.255
> 192.168.0.0 - 192.168.255.255
>
> We will refer to the first block as "24-bit block", the second as
> "20-bit block, and to the third as "16-bit" block. Note that the
> first block is nothing but a single class A network number, while the
> second block is a set of 16 contiguous class B network numbers, and
> third block is a set of 255 contiguous class C network numbers.
bye
Peter