Or he's using the machine as a personal VPN. Point is, all assumptions are useless. The fundamental problem here is that IP addresses are limited, but spam and

Or he's using the machine as a personal VPN. Point is, all assumptions are useless. The fundamental problem here is that IP addresses are limited, but spam and bad behavior originates from concentrated sources. Hosts are forced to defend against that behavior, and when the sources overlap minimally with their customers, they beat the perceived offenders with a cudgel of CAPTCHAs (and federated IP reputation databases, which you might call "eventually inconsistent"). Possible solutions: - Convince the Internet to diffuse its spam across the 0.0.0.0/8. This is pretty much impossible without some kind of decentralized mesh overlay network becoming mainstream and the primary method of consumer Internet access - Switch to IPv6 (I'm joking, but actually many filters are much less equipped to deal with IPv6 blocking than IPv4) - Ban IP reputation databases / threat sharing, or regulate it to be transparently verifiable that a new owner of an IP will not inherit its reputation. Considering the no-fly list continues to exist, which is inhibitive to rights more fundamental than web access, I wouldn’t expect this to happen any time soon. - Ban CAPTCHAs