pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
Sucuri - Website Protection, Malware Removal, and Blacklist Prevention
F5 Advanced Firewall Manager - Stop even the most massive and complex DDoS attacks with BIG-IP Advanced Firewall Manager: advanced data center protection against layer 3–4 threats.
Amazon CloudFront - Amazon CloudFront is a content delivery web service.
FireMon - FireMon Security Intelligence Platform delivers continuous visibility into and control over firewall infrastructure.
CloudFlare - Cloudflare is a global network designed to make everything you connect to the Internet secure, private, fast, and reliable.