VPN/Proxy detection is the process of identifying whether a user is accessing a website or online service using a virtual private network (VPN) or proxy server. VPNs and proxy servers allow users to hide their IP address and location, making it difficult for websites or online services to determine their true identity or location. While some users may use VPNs or proxies for legitimate reasons, such as accessing restricted content or protecting their online privacy, others may use them to engage in malicious activities, such as fraud or hacking.