I have a website where digital content is behind a paywall. We verify users have access by IP address. Our customers are all large companies, with static IP addresses. So, if a user is within the network of their company, then they automatically have access to our site. The problem is, we have no way of validating that the companies actually own every address on the list of addresses they give us.
Anyone have any ideas of how we verify that the companies actually own the IP addresses they are giving us.