VM instances that only have internal IP addresses (no external IP addresses) can use Private Google Access. They can reach the external IP addresses of Google APIs and services. The source IP address of the packet can be the primary internal IP address of the network interface or an address in an alias IP range that is assigned to the interface. If you disable Private Google Access, the VM instances can no longer reach Google APIs and services; they can only send traffic within the VPC network.
Private Google Access has no effect on instances that have external IP addresses. Instances with external IP addresses can access the internet, according to the internet access requirements. They don't need any special configuration to send requests to the external IP addresses of Google APIs and services.
You enable Private Google Access on a subnet by subnet basis; it's a setting for subnets in a VPC network. To enable a subnet for Private Google Access and to view the requirements, see Configuring Private Google Access.
Private Google Access permits access to Cloud and Developer APIs and most Google Cloud services, except for the following services:
- App Engine Memcache
Instead, private services access might support one or more of them.
The following diagram illustrates an implementation of Private Google Access.
The VPC network has been configured to meet the DNS, routing,
and firewall network requirements
for Google APIs and services. Private Google Access has been enabled on
subnet-a, but not on
VM A1can access Google APIs and services, including Cloud Storage, because its network interface is located in
subnet-a, which has Private Google Access enabled. Private Google Access applies to the instance because it only has an internal IP address.
VM B1cannot access Google APIs and services because it only has an internal IP address and Private Google Access is disabled for
VM B2can both access Google APIs and services, including Cloud Storage, because they each have external IP addresses. Private Google Access has no effect on whether or not these instances can access Google APIs and services because both have external IP addresses.
- To configure Private Google Access see Configuring Private Google Access.