In the days before HTTP1.1 and virtual interfaces, it would be easier to count the number of physical nodes on the Internet Not really: long before that machines could have multiple interfaces and thus multiple A records, and based on that counted as more than 1 physical node. As for private machines, running through a proxy, do we count these as Internet hosts, since they are not directly connected to the Internet and merely request proxies to contact internet services and relay information. Something similar goes for hosts on private internets: I wouldn't count those as Internet hosts. When we start talking dialup machines, it becomes more obvious that the count should try and focus on physical nodes. If an ISP has 2,000 customers and 30 modems, only 30 hosts will ever be using the internet at any one time, and only 30 IP addresses are being used to accomodate all 2,000 people. Therefore I would suggest that the ISP has 30 nodes. Again, this depends on the purpose of the hostcount. If you want to count the number of hosts that can be active at any time on the Internet, then this ISP should indeed be counted as 30 nodes/hosts. If however you want to count the number of hosts that comprise all of the Internet, then hosts that *can access* the Internet should be counted; in that case this ISP should be counted as 2000 nodes/hosts. But I still don't see the purpose of any attempt to give an "exact" hostcount: what difference does it make if a count would give 15.000.000 or 15.478.329 hosts/nodes? Piet