Use a DDoS protection service
Enable a content delivery network
Configure a web application firewall
Rate limit requests
Filter traffic with firewalls and ACLs
Use load balancing
Increase bandwidth and redundancy
Harden DNS infrastructure
Keep systems and software updated
Disable unnecessary services and ports
Monitor traffic continuously
Set up alerting and anomaly detection
Create an incident response plan
Use Anycast routing
Separate critical services from public-facing systems
Implement bot mitigation
Restrict access to admin interfaces
Use SYN cookies and connection limits
Coordinate with your ISP and hosting provider
Test defenses regularly