Networks

You can configure your own project-internal networks. Instances connected to the same internal subnet can communicate on Layer 2. The networks are entirely isolated from each other between projects as well as within a project. This way the same address ranges can be used as often as needed.

The instances can be supplied with address configurations over DHCP. You can create virtual routers to allow instances to communicate outside their own subnet

To make a server available to the outside so called Floating IPs can be used. This temporarily assigns a public IPv4 address to the port of the server instance. This way connections to the instance can be initiated from the outside as long as the rules of the security group permit it.

In this process an IP address is drawn randomly from the pool of the external network and assigned to the project. It can not be used by a different project until it is freed. IPs that need to be permanently accessible (e.g. through an assigned DNS name) should therefore not be returned to the pool.

Instances that don't have an assigned floating IP can establish outgoing connections (e.g. for OS updates) through a project-internal virtual router. Such VMs can not be accessed from the outside. All connections must be initiated by the instance itself.