How can I proactively harden my network to reduce the impact of a DDoS attack?

Proactive hardening includes implementing a strong firewall, using a CDN to absorb some of the attack traffic, employing source IP validation, implementing ingress filtering, keeping RouterOS updated, and regularly reviewing and optimizing your firewall rules. Having a DDoS response plan in place is also crucial, including contact information for your ISP and any DDoS mitigation services.