Here’s how to update an existing GCP firewall.
Ingress
gcloud compute firewall-rules update "firewall-rule-name" \ --description="firewall description" \ --priority="1000" --target-service-accounts="service-account@gserviceaccount.com" \ --source-ranges="10.0.0.0/8" --rules tcp:80,tcp:443,udp:1000-1100 |
Egress
gcloud compute firewall-rules update "firewall-rule-name" \ --description="firewall description" \ --priority="1000" --target-service-accounts="service-account@gserviceaccount.com" \ --destination-ranges="10.0.0.0/8" --rules tcp:80,tcp:443,udp:1000-1100 |