Check the AdsLab sender IP, and what Cloudflare does to it
Their postbacks come from one address. Enforcing it is free — unless you are behind Cloudflare, where REMOTE_ADDR is Cloudflare and the check rejects everything.
Tagged “cloudflare”
3 entries
Get the real client IP without trusting a spoofable header
Every per-IP limit you have is only as good as this function. Reading X-Forwarded-For unconditionally hands attackers a free reset on all of them.
Verify a Cloudflare Turnstile token server-side
The widget on the page proves nothing on its own. This is the server check, written to fail closed on every error path.