1. Introduction

The Dynamic Routing Gateway (DRG) is the heart of hybrid networking in OCI.
If you're connecting an on-prem network, another cloud provider, or multiple VCNs — the DRG is the router that ties it all together.

In this guide, I’ll show you exactly how to set it up, test it, and validate routing end-to-end.

2. What Problem This Solves

Without the DRG:

❌ On-prem cannot reach OCI
❌ Site-to-site VPN won’t work
❌ FastConnect can’t attach
❌ Cross-VCN routing becomes messy
❌ VCN peering becomes inconsistent

With a DRG:

✅ Centralized routing
✅ Multiple VCN attachments
✅ VPN or FastConnect integration
✅ Inspection and monitoring

Let's build it properly.

3. Step-by-Step Guide

Step 1 — Create DRG

OCI Console → Networking → Dynamic Routing Gateways → Create DRG

CLI:

Step 2 — Attach VCN to DRG

Console → DRG → Attachments → Create Attachment

CLI:

Step 3 — Create and Configure Route Tables

VCN → Route Tables → Create New Route Table

Add rule:

CLI:

Step 4 — Configure IPSec VPN (Optional)

Create Customer-Premise Equipment (CPE):

Create IPSec tunnel:

Step 5 — Validate Routing with Traceroute

From on-prem:

From OCI compute:

4. Architecture Diagram

(Generated in next message)

Placeholder:

5. Best Practices

• Use separate DRG route tables for each VCN attachment

• Avoid overlapping CIDRs

• Use HA VPN (tunnel 1 + tunnel 2)

• Consider FastConnect for production

• Enable logging on the DRG

• Use Network Path Analyzer for troubleshooting

6. Troubleshooting

7. Summary

The DRG allows you to build reliable hybrid networks in OCI.
With the configuration above, you can connect multiple VCNs and even full on-prem infrastructure using VPN or FastConnect.

👉 Download the free guide: “7 OCI Networking Mistakes to Avoid”
https://dmcloudarchitect.com/c/7_oci_mistakes_to_avoid.html