What are some best practices for hardening a SonicWall firewall against DDoS attacks?

Enable Geo-IP filtering for unwanted regions, implement rate limiting on critical services, keep the SonicWall firmware updated with the latest security patches, enable Capture ATP for cloud-based protection, regularly review firewall policies, and consider implementing a Web Application Firewall (WAF) for application-layer protection. Also, disable unnecessary services and ports.