Which HTTP headers does Cloudflare use to pass the original client IP address?

Cloudflare typically uses the following headers: `CF-Connecting-IP`, `X-Forwarded-For`, `X-Forwarded-Proto`, and `X-Real-IP`. `CF-Connecting-IP` is generally the most reliable as it represents the IP that directly connected to Cloudflare. `X-Forwarded-For` can be appended by multiple proxies, so it requires careful parsing.