Different gateways provide different access methods for communication between a VPC and external networks. The address blocks configured in the external subnet on the edge gateway determine the network space accessible to the edge gateway:
Floating IP address block: After a virtual machine is bound to a floating IP, the external networks reachable by the virtual machine are those reachable by the floating IP address block.
NAT gateway address block: After a NAT gateway is configured for a VPC subnet, virtual machines in the VPC subnet can access the external networks reachable by the NAT gateway address block via SNAT. External networks that can access the NAT gateway address block can also access services inside the VPC via DNAT.
Routing gateway address block: After a routing gateway is configured for a VPC subnet, the reachable external networks are a subset of those reachable by the routing gateway address block, as it also depends on the route configuration for the VPC subnet CIDR in the external network.
