What is a DDoS Attack? How they Work + Protection Strategies | UpGuard

This document provides a structured overview of DDoS attacks, explaining botnet-driven overloads (often via compromised IoT devices), the distinction between DoS and DDoS, and detailing attack categories: volume-based (ICMP/UDP floods), protocol/network-layer (SYN floods, Smurf), and application-layer (L7) vectors. It outlines mitigation strategies such as ICMP rate limiting with upstream controls, backlog tuning/recycling, SYN cookies, intelligent firewalls, and disabling IP broadcast for legacy systems, and notes operational warning signs like slow loading, 503 errors, and repeated connections to a single port observed in server logs.