Eric,
The many answers to your questions are in RFC 2993 and in
http://www.ietf.org/internet-drafts/draft-ietf-nat-protocol-complications-06.txt
(which will soon be an RFC).
Brian
TOMSON ERIC wrote:
<EXAMPLES>
<EXAMPLE 1> I have a CATV connection at home. I get only 1 dynamic public IP
address. However, I have a small internal network (some couple of computers).
How can I guarantee a full Internet access to each one of these computers? =>
By installing W2K A.S. with NAT on a PC having 2 NICs (1 NIC connected to the
CATV modem, 1 NIC connected to a switch), allowing a full transparent
Internet access to an undetermined number of PC on my private LAN (depending
on the range of private addresses I use). </EXAMPLE 1>
<EXAMPLE 2> A company has a LAN composed of hundreds of computers and wants
to give some limited access to the Internet, to its internal network. They
subscribe to an ISP and ask for 10 fixed addresses. They install a router and
configure it with NAT in such a way that any 10 internal hosts can have
concurrent connections to the Net by dynamically getting a temporary map
between their internal address and one of the 10 public addresses. As soon as
a PC disconnects, its mapped address can be assigned to someone else.
</EXAMPLE 2>
</EXAMPLES>
<QUESTIONS>
* What is the problem using NAT in any of these 2 examples?
* Since routers only work on network addresses and not on host addresses,
what is the problem - for any routing table - of using NAT in any of these 2
examples (in case 1, only the network ID of the unique official address has
to be known by the Net ; in case 2, most probably 1 unique network ID will be
used by the 10 official addresses)?
</QUESTIONS>
<COMMENT>
By the way, IPv6 brings much more answers than just a solution to the address
space (which is not simply 4 times wider - which could be achieved but simply
adding 2 bits to the 32 bits of IPv4 - but actually 2*2*2*...[128-32=96
times]...*2 times wider, i.e. 2^96 times wider) : [host, routing and network]
autoconfiguration, quality of service, better and more efficient IP headers,
security, performance, mobility,...
</COMMENT>
E.T.