System Design Article

DDoS Protection, WAF & Security Best Practices

Difficulty: Hard

DDoS attacks try to exhaust your bandwidth, your TCP stack, your application capacity, or your downstream dependencies. A WAF (web application firewall) tries to block exploit traffic before it reaches your code. Together with rate limiting, bot management, anti-abuse tooling, and a hardened application layer, they form the defensive perimeter that real production systems live behind. This lesson covers the layered defense: edge / CDN scrubbing for L3/L4 floods, rate limiting and bot detection for L7 abuse, WAF rules for OWASP-class exploits, the OWASP Top 10 with concrete mitigations, secure development practices (input validation, output encoding, secrets management, dependency hygiene), incident response, and the operational realities of running this stack (false positives, vendor selection, escalation, post-mortems). The goal is to leave you able to design and defend the security perimeter for any user-facing system.