Why this week matters: DDoS attacks are the most common attack against internet-facing services. Understanding the mechanics lets you evaluate DDoS vendors (Cloudflare, AWS Shield, Akamai), configure existing defenses correctly, and architect a first line of defense using nothing but the Go standard library.
Background in this wiki: TCP/IP guide Ch 21 (SYN floods and SYN cookies), Ch 52 (SYN and accept queues, overflowed on purpose), Ch 20 (UDP); HTTPS guide Ch 19 (Slowloris, measured), Ch 21 (rate limiting), Ch 23 (burn-rate alerting). Security in Depth: Chapter 40B (rate limiting in depth) and Chapter 28 (resilience as a security property).