03 ‐ Difference ‐ Service Gateway, NAT Gateway & Internet Gateway - SanjeevOCI/Study GitHub Wiki
Here is a specific comparison between Service Gateway, NAT Gateway, and Internet Gateway in Oracle Cloud Infrastructure (OCI):
| Feature | Service Gateway | NAT Gateway | Internet Gateway |
|---|---|---|---|
| Purpose | Enables private resources to access OCI services without using the public internet. | Allows private resources to access the internet for outbound traffic only. | Provides public access to resources in a VCN for both inbound and outbound traffic. |
| Traffic Direction | Outbound only (to OCI services). | Outbound only (to the internet). | Both inbound and outbound (to/from the internet). |
| Use Case | Accessing OCI services like Object Storage, Autonomous DB, etc., from private subnets. | Accessing the internet from private subnets (e.g., for updates, patches). | Hosting public-facing applications or services (e.g., web servers). |
| Public IP Required | No | No | Yes (resources must have a public IP). |
| Security | Traffic stays within OCI's private network. | Traffic goes through the internet but is initiated by private resources. | Traffic is fully exposed to the public internet. |
| Example Scenario | A private VM accessing Object Storage to store backups. | A private VM downloading OS updates from the internet. | A public-facing web server accessible from the internet. |
| Route Table Target | Service Gateway | NAT Gateway | Internet Gateway |
Key Differences
-
Service Gateway:
- Used for accessing OCI services (e.g., Object Storage, Autonomous DB) privately.
- Does not require a public IP.
- Traffic does not leave OCI's private network.
-
NAT Gateway:
- Used for outbound internet access from private subnets.
- Does not allow inbound traffic.
- Resources in private subnets remain hidden from the internet.
-
Internet Gateway:
- Used for public internet access (both inbound and outbound).
- Requires resources to have a public IP.
- Suitable for hosting public-facing applications.
When to Use Each Gateway
- Service Gateway: When you need private access to OCI services without exposing resources to the internet.
- NAT Gateway: When private resources need outbound internet access (e.g., downloading updates).
- Internet Gateway: When resources need to be publicly accessible (e.g., hosting a website).
This comparison highlights the specific use cases and differences between the three gateways in OCI.