[LINK] IPv4 host density measured by ping

[Adrian Chadd]

On Thu, Mar 01, 2007, Robin Whittle wrote:

> If this is the usual case, with modems generally being set not to
> respond to pings, then I don't understand why I get so many acks from
> the prefixes I scanned.  I imagine an ISP would prefer ping responses to
> be enabled in order to help monitor their network.

You'd think that, but I believe XP firewall has an option to block ICMP
ping replies and this -has- bitten me when trying to debug arbitrary
network issues.

Your scanning might pick up IPv4 allocations but it won't pick up the
number of "connected computers". NAT/firewall's throw that all in the bin,
and there's large chunks of end-users connected that way.

The only accurate way to measure how many connected computers there are
would be to run a really popular bit of internet content and do some
tricks to "sniff" individual end-users. Like, say, Google.



Adrian