Configuring Your On-Premises Router for an IPSec VPN

This topic is for network administrators. It explains how to configure the on-premises router at your end of the IPSec VPN so traffic can flow between your on-premises network and virtual cloud network (VCN). See these related topics:

The following figure shows the basic layout of the IPSec VPN connection.

This image summarizes the general layout of the IPSec connection and tunnels.

Requirements and Prerequisites

There are several requirements and prerequisites to be aware of before moving forward.

Asymmetric Routing

Oracle uses asymmetric routing across the multiple tunnels that make up the IPSec VPN connection. Even if you configure one tunnel as primary and another as backup, traffic from your VCN to your on-premises network can use any tunnel that is "up" on your device. Make sure to configure your firewalls accordingly. Otherwise, ping tests or application traffic across the connection will not reliably work.

Exception: Cisco ASA policy-based configuration, which uses a single tunnel.

Creation of Cloud Network Components

You or someone in your organization must have already used Networking to create a VCN and an IPSec connection, which consists of multiple IPSec tunnels for redundancy. You must gather the following information about those components:

  • VCN ID: The VCN ID has a UUID at the end. You can use this UUID, or any other string that helps you identify this VCN in the device configuration and doesn't conflict with other object-group or access-list names.
  • VCN CIDR
  • VCN CIDR subnet mask
  • For each IPSec tunnel:
    • The IP address of the Oracle IPSec tunnel endpoint (the VPN headend)
    • The pre-shared key (PSK)

Information about Your On-Premises Router

You also need some basic information about the inside and outside interfaces of your on-premises router. For more information, see the configuration topic for your type of router.

IPSec VPN Best Practices

  • Configure all tunnels for every IPSec connection: Oracle deploys multiple IPSec headends for all your connections to provide high availability for your mission-critical workloads. Configuring all the available tunnels is a key part of the "Design for Failure" philosophy. (Exception: Cisco ASA policy-based configuration, which uses a single tunnel.)
  • Have redundant CPEs in your customer premise locations: Each of your sites that connects via IPSec to Oracle Cloud Infrastructure should have redundant CPE devices. If you add each CPE to the Oracle Cloud Infrastructure Console and create an IPSec connection between your dynamic routing gateway (DRG) and each CPE, Oracle will provision a full mesh of tunnel endpoints on the Oracle IPSec headends to your CPEs. The Oracle network dynamically learns which tunnels are up and uses the optimal one based on tunnel state and location.
  • Consider backup aggregate routes: If you have multiple sites connected via IPSec VPNs to Oracle Cloud Infrastructure, and those sites are connected to your on-premises backbone routers, consider configuring your IPSec connection routes with both the local site aggregate route as well as a default route.

    Note that the DRG routes learned from the IPSec connections are only used by traffic you route from your VCN to your DRG. The default route will only be used by traffic sent to your DRG whose destination IP address does not match the more specific routes of any of your tunnels.

Confirming the Status of the Connection

After you configure the IPSec connection, you can test the connection by launching an instance into the VCN and then pinging it from your on-premises network. For information about launching an instance, see Launching an Instance.

You can get the status of the IPSec tunnels in the API or Console. For instructions, see To get the status and configuration information for the IPSec tunnels.

Device Configurations