If you want to enable access to your instance over the public Internet, you must associate a public IP address with your instance. You can associate either a temporary or a persistent public IP address with an instance when you create the instance.
Temporary public IP addresses are assigned dynamically from a pool of public IP addresses. When you associate a temporary public IP address with an instance, if the instance is restarted or is deleted and created again later, its public IP address might change. If you want to assign a persistent public IP address to your instance, you must first create an IP reservation, and then associate the IP reservation with the instance.
By default, a /29 (8 IP addresses) for outbound source NAT and a /28 (16 IP addresses) for inbound NAT are available for each SPARC Model 300 Service. The /29 outbound IPs are a NAT pool for dynamic NAT of the instances to other Oracle Cloud services or to other public addresses. All network traffic from the compute instances on the outbound NAT are temporary public IPs.
The /28 inbound IPs use static mapping/persistent to instances or zones. You need to request these IPs (and additional public IP addresses) by submitting a service request (SR). Typically, hosts that require public facing services will need these.