step-by-step process to create an Internet Gateway in Oracle Cloud Infrastructure (OCI)

and attach it to a Public subnet using a custom route table:

Step-by-Step Process

1. Create an Internet Gateway (IGW)

• Navigate to the Networking section in the OCI Console.
• Open your Virtual Cloud Network (VCN).

• Under the “Gateways” menu, go to Internet Gateways.
• Click Create Internet Gateway.
  • Enter a friendly name.

• Choose the appropriate compartment.

• Click Create Internet Gateway. Your IGW is now attached to this VCN but not yet in use by any subnet.

2. Create/Identify the Route Table

• Still within your VCN, click on Routing tab.
• For good practice and better management, create a new custom route table for your public subnet, or identify the one you want to use.
  • Click Create Route Table or use an existing one.
  • Give it a descriptive name.

3. Add a Route Rule to the Route Table

• In the chosen custom route table, click Add Route Rules.

• Enter the following for the route rule:
  • Destination CIDR Block: 0.0.0.0/0 (routes all outbound traffic to the internet)
  • Target Type: Internet Gateway
  • Target Internet Gateway: Select the IGW you just created.

• Click Add Route Rule to save it.

4. Attach Route Table to Public Subnet

• In VCN's menu, click Subnets.

• Click on your public subnet.

• Click Edit.

• Change/Set the associated route table to your new (or desired) custom route table.
• Save changes.

5. Configure Security Rules (if needed)

• Make sure the security list or network security group (NSG) associated with your public subnet has the necessary ingress (e.g., TCP/22 for SSH, HTTP/80, HTTPS/443) and egress rules to allow internet access.
• If you use the default security list, review default rules and add custom ones if required.

Summary Table

Task	Where to Do It	Key Setting or Action
Create Internet Gateway	VCN > Internet Gateways	Name, Compartment, Enable
Create/Choose Custom Route Table	VCN > Route Tables	Name, (optional: Description)
Add Route Rule for IGW	Selected Route Table	Dest: 0.0.0.0/0 → Target: IGW
Attach Route Table to Public Subnet	VCN > Subnets > [Subnet Name]	Set Route Table to Custom Table
Set Security Rules for Subnet	VCN > Security Lists/NSGs	Ingress/Egress for required ports