Peter Ford <peterf(_at_)exchange(_dot_)microsoft(_dot_)com>:
Run a market survey and you will find out why people buy these NAT
devices. It shouldn't be that hard, you can hire one of many consumer
research firms to do that kind of quantative research for you.
Who needs market research? All you have to do is look at the cost-feature
profile of the most popular NATs and notice who they were designed for.
Those vendors have already done the market research and bet real money on the
Downstairs in my basement I have a Linksys firewalling router that does NAT.
Like millions of other SOHO users, I needed NAT in order to be able to connect
a home network of multiple machines to a DSL or cable line. The ISP gave
me only one IP address; the NAT allows me to have several clients and one
server behind it. (This particular box, as is now common, is also a
WiFI access point.)
The other thing NAT does is allow me to decouple my local IP addresses
from the ISP's assignment. So all my local machines can keep
192.168.1.x regardless of what address the world thinks my server has.
Because I have a static address (18.104.22.168) this is merely a
convenience that would make it easy for me to change ISPs if I had to;
if, like many ISP users, I had a DHCP-allocated dynamic one, it would
be a necessity.
To sum up, NAT gives me two features:
1. Multiple machines on the single-address allocation the ISP gives me.
2. Decoupling of mt local network addresses from the ISP assignment.
The Linksys, which is probably the single most popular brand, was designed
for exactly this set of requirements. So are most of its competition -- the
Belkins, the Netgears, the AirStations, etc.
I hear a lot of muttering about NATs being evil. I really don't have an
opinion on the subject -- I understand some of the theoretical problems,
but they've never bitten me. So, asking as a network administrator,
how would the implied problems be solved in an IPv6 world?
<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>
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