How to ensure that a request is really proxied by CloudFlare?
问题 In one of projects we use CloudFlare and its cf-connecting-ip header to get a visitor IP address. But I'm not sure that the info can be fully trusted. For example, a bad user somehow had obtained real IP of our server, and connecting directly to it, putting fake IP address to the cf-connecting-ip header, and pretending that it was a legitimate CF-proxied request. I examined headers for CF-proxied requests, and saw the cf-request-id header. But it's unique per a request, and I cannot see there