LAB 31 ‐ Validate DRG Route Rules for VCN Attachments - gautam-amitesh/OCI GitHub Wiki

When we provision a DRG we see a pop-up saying Dynamic routing gateway and associated resources have been created successfully., here associated resources refer to child resources which include Default DRG Route Tables.

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Inside DRG when we navigate to Routing we can see there are two Route Tables, one for VCN attachments and another one for RPC, VC, and IPSec attachments.

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Inside Autogenerated Drg Route Table for VCN attachments when we click Get all route rules we did not find any route rule because till now we have not create any VCN attachment.

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When we will create VCN attachments then it will dynamically update route rules when we will attach VCNs to it, by default in OCI DRG Route Rules are created for VCNS not the subnet which we can verify by looking at the Destination CIDR.

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Now if we verify the dynamic route updation by navigating to Autogenerated Drg Route Table for VCN attachments > Get all route rules it will show the updated routes.

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Now if we even add new subnets into our VCNs the current DRG Route Table will remain intact.

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Now after we click Refresh table we can still see our DRG Route Rules is intact due to its attachment with VCN not the subnet. If it was attached to subnets like if we see our subnet CIDR block in Destination CIDR block then the OCI would have added route rules for new private_subnet-02.