Employ network load balancing for traffic distribution. Update Identity-Aware Proxy (IAP) policies to allow only administrative access. Implement custom firewall rules on all external IP addresses.

Set up firewall rules on Compute Engine instances within the application's environment. Rely on load balancers for threat detection. Increase instance resources to cope with attack volume.

Add firewall rules that restrict all internal IP ranges. Establish Cloud DNS security policies. Disable external IP addresses to reduce the attack surface. Create user groups for access control.