Internet Gets First Census in 25 years - So?
Due to security settings on some servers, about 61% of the pings received no response at all, and others received responses equivalent to "no comment". Millions of servers did respond, though, allowing Heidemann and Pradkin to build an 'atlas of the internet.'
"To our knowledge," says Heidemann, "the only other census of the Internet was in 1982, when the Internet consisted of 315 allocated addresses."
What's the point, however, of doing such an exercise, if most servers / routers block pings? That should have been obvious from the start. With the security measures even on home routers of not responding to a ping, this sort of survey is useless.