An IP Address, also known as "Internet Protocol", is a unique identifier assigned to a user browsing the internet through their Internet Service Provider (ISP). Just as we use an email address or phone number to identify a person, an IP address is linked to an individual user and can be associated with their online activity. An IP reputation check for each IP address makes it easy to identify high risk users or suspicious payments and clicks. It can be difficult for users to frequently switch an assigned IP address from their ISP, which is why internet users often use proxies, VPNs, or Tor to mask their identity.