Jiri Kuthan wrote:
Hello,
as the discussion departed from my original question to
the favorite discussion on NAT/ipv6/etc architectural issues,
I would like to re-raise the question:
"is anyone aware of any estimations of fraction of Internet users
who are behind firewalls and NATs?"
Before it goes off into DNS name administration:
None that I've heard of. From the perspective of those inside the NAT
firewall, the fact that outside world can't tell the size of the hidden
network is an advantage.
One could ask a sample of administrators and extrapolate the results
but, again, the problem becomes how confident you could be of the
results if you don't get a very significant response rate (I tried
something like this a number of years ago when attempting to estimate
the proportion of assigned IPv4 addresses were actually being used:
expect a healthy degree of skepticism if the queries are coming out of
the blue).
Even if that were possible or in a world without NATs, though: are you
assuming a 1:1 mapping between IP addresses and 'users'? Between
mainframes in one direction and folks surrounded by multiple machines in
the other, which way do you go? Is there a 'user' associated with a web
server; if so, what if you've got a load balancer in front?
-- Frank