You create an egress firewall rule that allows TCP connections from your VM to external hosts. Do you also need to create an ingress rule to permit the response packets from those external hosts?

Google Cloud's firewall is stateful, meaning it tracks the state of connections. When an egress rule permits an outbound TCP connection, the firewall automatically allows the corresponding inbound return traffic for that established connection. This eliminates the need to create a separate ingress rule for response packets, simplifying firewall management. Creating a separate ingress rule for established/related traffic is unnecessary because the stateful nature handles it. VPC route entries are for packet forwarding paths, not firewall permissions for return traffic. IP forwarding on a VM is for routing packets between network interfaces on the VM itself, not for allowing external responses through the firewall.