There are blocks of addresses reserved for private networks (RFC
Class A private networks
Class B private networks
Class C Private networks
You can use private network addresses any way you want (sort of). By
design, these addresses cannot travel across the internet -- that
keeps them "private". Any self-respecting internet router will refuse
to forward packets to/from these addresses. That means that you
should never see a private address in one of those ranges unless
perhaps your ISP uses one of them. In that case your mail server,
news server, etc. might be visible to you as a private address. If
your ISP uses a private address range, then avoid using that yourself.
You might ask: How do I get on the internet when I have a private
address? The answer is simple: it is the interface (network card,
modem PPP connection, etc.) that has an IP address, not the computer.
Computers can and do have more than one interface. So your computer
can simultanesously have a private address of 192.168.88.8 and a
public IP address of 22.214.171.124.
When you dial up you are temporarily assigned a globally valid IP
address for the duration of your session. It gets re-assigned to the
next caller when you hang up (or get hung up on).
>I've just connected by two linux machines together, recompiled kernel
>many times to install hardware, and am now trying to get a tiny
>going. I connect to the internet via a dial up using pppd. I can
>telnet between my two machines - but so far I've just used some
>arbitrary network identifier
>My question is, what network address should I use for my machines -
>x.x.x.mymachine bit...? Does it matter if there's another network
>there with the same address? I know you have to register domain
>but what about IP addresses?
>Forgive me if I'm being an idiot - I'm quite pleased I've got this