Firewall Rules are one of the best security features we released this year, and have been an overwhelming success. Customers have been using Firewall Rules to solve interesting security related use cases.
Threat landscapes change every second. As attackers evolve, vulnerabilities materialise faster than engineers can patch systems becoming more dynamic and devious. Part of Cloudflare’s mission is to keep you and your applications safe.
This blog post is very old now. You probably don't want to use the techniques described here. GO'S sync.Pool is a better way to go.