This topic explains how to set up Scenario C, which is a simple example of a multi-tier setup. It consists of a Virtual Cloud Network (VCN) with a regional public subnet to hold public servers (such as web servers), and a regional private subnet to hold private servers (such as database servers). Servers are in separate availability domains for redundancy.
The VCN has a dynamic routing gateway (DRG) and Site-to-Site VPN for connectivity to your on-premises network.
Instances in the public subnet have direct access to the internet by way of an internet gateway . Instances in the private
subnet can initiate internet connections by way of a NAT
gateway (for example, to get software updates), but cannot receive inbound
connections from the internet through that gateway.
Each subnet uses the default security
list, which has default rules that are designed to make it easy to get
started with Oracle Cloud Infrastructure. The rules enable typical
required access (for example, inbound SSH connections and any type of outbound
connections). Remember that security list rules only allow traffic. Any traffic
not explicitly covered by a security list rule is denied.
Tip
Security lists are one way to control traffic in and out of the VCN's resources. You can also use network security groups
Each subnet also has its own custom security list and custom route table with rules specific to the needs of the subnet's instances. In this scenario, the VCN's default route table (which is always empty to start with) is not used.
To set up the VPN in this scenario, you need to get the following information from a network administrator:
Public IP address of the customer-premises equipment (CPE) at your end of the VPN
Static routes for your on-premises network (this scenario uses static routing for the VPN tunnels, but you could instead use BGP dynamic routing)
You provide Oracle this information and in return receive the information your network
administrator needs to configure the on-premises router at your end of the VPN.
Required IAM Policy
To use Oracle Cloud Infrastructure, an administrator must be a member of a group granted security access in a policy by a tenancy administrator. This access is required whether you're using the Console or the REST API with an SDK, CLI, or other tool. If you get a message that you don't have permission or are unauthorized, verify with the tenancy administrator what type of access you have and which compartment your access works in.
If you're a member of the Administrators group, you already have the required access
to implement Scenario C. Otherwise, you need access to Networking, and you need the ability to launch
instances. See IAM Policies for Networking.
Setting Up Scenario C 🔗
Setup is easy in the Console. Alternatively, you can use
the Oracle Cloud Infrastructure API, which lets you implement the
individual operations yourself.
Important
Most of this process involves working with the Console or API (whichever you choose) for a short period
to set up the required Networking components. There's also
a critical step that requires a network administrator in your organization to take
information you receive while setting up the components and use it to configure the
on-premises router at your end of the VPN. Therefore you can't complete this process in
one short session. Take a break while the network administrator completes the
configuration and then confirm communication with your instances over the VPN.
Open the navigation menu , select Networking, and then select Virtual cloud networks.
Under List Scope, select a compartment that you have permission to work in.The page updates to display only the resources in that compartment. If you're not sure which compartment to use, contact an administrator. For more information, see Access Control.
Click Create Virtual Cloud Network.
Enter the following:
Name: A friendly name for the VCN. It doesn't have to be
unique, and it cannot be changed later in the Console (but you can
change it with the API). Avoid entering confidential information.
Create in Compartment: Leave as is.
CIDR Block: One or more non-overlapping CIDR blocks for the
VCN. For example: 172.16.0.0/16. You can add or remove CIDR blocks
later. See Allowed VCN Size and Address Ranges. For reference, here's a CIDR calculator.
Enable IPv6 Address Assignment: IPv6 addressing is supported
for all commercial and government regions. For more information, see
IPv6 Addresses.
Use DNS Hostnames in this VCN:
This option is required to assign DNS hostnames to hosts in the VCN, and required if you plan to use the VCN's default DNS feature (called the Internet and VCN Resolver). If you select this option you can specify a DNS Label for the VCN, or you can let the Console to generate one for you. The dialog box automatically displays the corresponding DNS Domain Name for the VCN (<VCN_DNS_label>.oraclevcn.com). For more information, see DNS in Your Virtual Cloud Network.
Tags: Leave as is. You can add tags later if you want. For more information, see Resource Tags.
Click Create Virtual Cloud Network.
The VCN is then created and displayed on the Virtual Cloud Networks page in the compartment you chose.
Create an internet gateway for your VCN:
Under Resources, click Internet Gateways.
Click Create Internet Gateway.
Enter the following:
Name: A friendly name for the internet gateway. It doesn't
have to be unique, and it cannot be changed later in the Console
(but you can change it with the API). Avoid entering confidential information.
Create in Compartment: Leave as is.
Tags: Leave as is. You can add tags later if you want. For more information, see Resource Tags.
Click Create Internet Gateway.
The internet gateway is then created and listed on the page.
Create a NAT gateway for your VCN:
Under Resources, click NAT Gateways.
Click Create NAT Gateway.
Enter the following:
Name: A friendly name for the NAT gateway. It doesn't have to
be unique, and it cannot be changed later in the Console (but you
can change it with the API). Avoid entering confidential information.
Create in Compartment: Leave as is.
Tags: Leave as is. You can add tags later if you want. For more information, see Resource Tags.
Click Create NAT Gateway.
The NAT gateway is then created and listed on the page.
Create the custom route table for the public subnet (which you create
later):
Under Resources, click Route Tables.
Click Create Route Table.
Enter the following:
Name: A friendly name for the route table (for example,
Public Subnet Route Table). It doesn't have to be unique,
and it cannot be changed later in the Console (but you can change it with
the API). Avoid entering confidential information.
Create in Compartment: Leave the default value (the compartment you're currently working in).
Click + Additional Route Rule and enter the following:
Target Type: Internet Gateway.
Destination CIDR Block: 0.0.0.0/0 (which means that
all non-intra-VCN traffic that is not already covered by
other rules in the route table goes to the target specified
in this rule).
Compartment: Leave as is.
Target: The internet gateway you created.
Description: An optional description of the rule.
Tags: Leave as is. You can add tags later. For more information, see Resource Tags.
Click Create Route Table.
The route table is then created and listed on the page.
Create the custom route table for the private subnet (which you create
later):
Click Create Route Table.
Enter the following:
Name: A friendly name for the route table (for example,
Private Subnet Route Table). It doesn't have to be
unique, and it cannot be changed later in the Console (but you can change it with
the API). Avoid entering confidential information.
Create in Compartment: Leave the default value (the compartment you're currently working in).
Click + Additional Route Rule and enter the following:
Target Type: NAT Gateway.
Destination CIDR Block: 0.0.0.0/0 (which means that
all non-intra-VCN traffic that is not already covered by
other rules in the route table goes to the target specified
in this rule).
Compartment: Leave as is.
Target: The NAT gateway you created.
Description: An optional description of the rule.
Tags: Leave as is. You can add tags later. For more information, see Resource Tags.
Click Create Route Table.
The route table is then created and listed on the page. After you
set up Site-to-Site VPN, you update the Private
Subnet Route Table so it routes traffic from the private subnet to the
on-premises network by way of the DRG.
Update the default
security list to include rules to allow the types of connections that
your instances in the VCN need:
Under Resources, click Security Lists.
Click the default security list to view its details. By default, you land on the Ingress Rules page.
Edit each of the existing stateful ingress rules so that the Source CIDR is the CIDR for your on-premises network (10.0.0.0/16 in this example) and not 0.0.0.0/0. To edit an existing rule, click the Actions menu () for the rule, and then click Edit.
If you plan to launch Windows instances, add a rule to enable RDP access:
Create a custom security list for the public subnet:
Return to the Security Lists page for the VCN.
Click Create Security List.
Enter the following:
Name: Enter a friendly name for the list (for example,
Public Subnet Security List). It doesn't have to be
unique, and it cannot be changed later in the Console (but you can
change it with the API). Avoid entering confidential information.
Create in Compartment: Leave the default value (the compartment you're currently working in).
The custom security list for the public subnet is then created and listed on the page.
Create a custom security list for the private subnet:
Click Create Security List.
Enter the following:
Name: Enter a friendly name for the list (for example,
Private Subnet Security List). It doesn't have to be
unique, and it cannot be changed later in the Console (but you can
change it with the API). Avoid entering confidential information.
Create in Compartment: Leave the default value (the compartment you're currently working in).
Add the following ingress rules:
Example: Ingress SQL*Net access from clients in the public subnet
Source CIDR: CIDR for the private subnet (172.16.2.0/24
in this example)
IP Protocol: TCP
Source Port Range: All
Destination Port Range: 1521
Description: An optional description of the rule.
Add the following egress rules:
Click Create Security List.
The custom security list for the private subnet is then created and listed on the page.
Create the subnets in the VCN:
Under Resources, click Subnets.
Click Create Subnet.
Enter the following:
Name: A friendly name for the regional public subnet (for
example, Regional Private Subnet). It doesn't have to be
unique, and it cannot be changed later in the Console (but you can
change it with the API). Avoid entering confidential information.
Regional or Availability Domain-Specific: Select Regional (recommended), which
means the subnet spans all availability domains in the region.
Later when you launch an instance, you can create it any
availability domain in the region. For more information, see Overview of VCNs and Subnets.
CIDR Block: A single, contiguous CIDR block within the VCN's
CIDR block. For example: 172.16.1.0/24. You cannot change
this value later. For reference, here's a CIDR calculator.
Enable IPv6 Address Assignment: This option is available only
if the VCN is enabled for IPv6. IPv6 addressing is supported for all
commercial and government regions. For more information, see IPv6 Addresses.
Route Table: Select the Private Subnet Route Table you created earlier.
Private or public subnet: Select Private Subnet, which means VNICs in the subnet are not allowed to have public IP addresses. For more information, see Access to the Internet.
Use DNS Hostnames in this Subnet:
This option is available only if a DNS label was
provided for the VCN when it was created. The option is required for assignment
of DNS hostnames to hosts in the subnet, and also when you plan to use the VCN's
default DNS feature (called the Internet and VCN Resolver). If you select
the checkbox, you can specify a DNS label for the subnet, or let the Console generate one for you. The dialog box
automatically displays the corresponding DNS domain name for the subnet as an
FQDN. For more information, see DNS in Your Virtual Cloud Network.
DHCP Options: Select the default set of DHCP options.
Security Lists: Select two security lists: Both the default security list and the Private Subnet Security List you created earlier.
Click Create Subnet.
The private subnet is then created and displayed on the Subnets page.
Repeat the preceding steps a-d to create the regional public subnet. Instead use a name such as Regional Public Subnet, select Public Subnet instead of Private Subnet, use the Public Subnet Route Table, and use both the default security list and Public Subnet Security List you created earlier.
You can now create one or more instances in the subnet (see Launching an Instance). The scenario's diagram shows instances in two different availability domains. When you create the instance, you choose the AD, which VCN and subnet to use, and several other characteristics.
For each instance in the public subnet, you must assign the instance a public IP address.
Otherwise, the instance isn't available from your on-premises network.
You can't yet reach the instances in the private subnet because there's no gateway
connecting the VCN to your on-premises network. The next procedure walks you through
setting up Site-to-Site VPN to enable that communication.
Open the navigation menu and select Networking. Under Customer connectivity, select Customer-premises equipment.
Click Create Customer-Premises Equipment.
Enter the following:
Create in Compartment: Leave the default value (the compartment you're currently working in).
Name: A friendly name for the customer-premises equipment
object. It doesn't have to be unique, and it cannot be changed later
in the Console (but you can change it with the API). Avoid entering confidential information.
IP Address: The IP address of the on-premises router at your end of the VPN (see Prerequisites).
Click Create.
The CPE object is in the "Provisioning" state for a short period.
Create a Dynamic Routing Gateway (DRG):
Open the navigation menu and select Networking. Under Customer connectivity, select Dynamic routing gateway.
Click Create Dynamic Routing Gateway.
For Create in Compartment: Leave the default value (the compartment you're currently working in).
Enter a friendly name for the DRG. It doesn't have to be unique, and it
cannot be changed later in the Console (but you can change it with the API).
Avoid entering confidential information.
Click Create.
The DRG is in the "Provisioning" state for a short period. Wait
until it is fully provisioned before continuing.
Attach the DRG to your VCN:
Click the DRG that you created.
Under Resources, click Virtual Cloud Networks.
Click Attach to Virtual Cloud Network.
Select the VCN. Ignore the section for advanced options, which is only for an advanced routing scenario called transit routing, which is not relevant here.
Click Attach.
The attachment is in the "Attaching" state for a short
period.
Update the private subnet's route table (which already has one rule for the NAT gateway):
Open the navigation menu , select Networking, and then select Virtual cloud networks.
Click your VCN.
Click Route Tables, and then click the Private Subnet Route Table you created earlier.
Click Add Route Rule.
Enter the following:
Target Type: Dynamic Routing Gateway. The VCN's attached DRG is automatically selected as the target, and you don't have to specify the target yourself.
Destination CIDR Block: 0.0.0.0/0 (which means that all
non-intra-VCN traffic that is not already covered by other rules in
the route table goes to the target specified in this rule).
Description: An optional description of the rule.
Click Add Route Rule.
The table is updated to route any traffic destined for your on-premises network to the DRG. The original rule for 0.0.0.0/0 routes any remaining traffic leaving the subnet to the NAT gateway.
Create an IPSec Connection:
Open the navigation menu and select Networking. Under Customer connectivity, select Site-to-Site VPN.
Click Create IPSec Connection.
Enter the following:
Create in Compartment: Leave the default value (the compartment you're currently working in).
Name: Enter a friendly name for the IPSec connection. It
doesn't have to be unique. Avoid entering confidential information.
Customer-Premises Equipment Compartment: Leave as is (the VCN's compartment).
Customer-Premises Equipment: Select the CPE object you created earlier.
Dynamic Routing Gateway Compartment: Leave as is (the VCN's compartment).
Dynamic Routing Gateway: Select the DRG that you created earlier.
Static Route CIDR: Enter at least one static route CIDR (see
Prerequisites). If you need
to add another, click Add Static Route. You can enter up to
10 static routes, and you can change the static routes later.
Click Show Advanced Options and optionally provide the following items:
CPE IKE Identifier: Oracle defaults to using the public IP address of the CPE. But if your CPE is behind a NAT device, you might need to enter a different value. You can either enter the new value here, or change the value later.
Tags: Leave as is. You can add tags later. For more information, see Resource Tags.
Click Create IPSec Connection.
The IPSec connection is created and displayed on the page. The
connection is in the Provisioning state for a short period.
The displayed tunnel information includes the IP address of the VPN headend and the tunnel's IPSec status (possible values are Up, Down, and Down for Maintenance). At this point, the status is Down. To view the tunnel's shared secret, click the Actions menu (), and then click View Shared Secret.
Copy the Oracle VPN IP address and shared secret for each of the
tunnels to an email or other location so you can deliver it to the
network engineer who configures the on-premises router.
For more information, see CPE Configuration. You can view this tunnel information here in the Console at any time.
You have now created all the components required for Site-to-Site VPN.
Next, your network administrator must configure the on-premises router before network
traffic can flow between your on-premises network and VCN.
Configure your on-premises router according to the information in CPE Configuration.
If compute instances are already in one of the subnets, you can confirm the IPSec
connection is up and running by connecting to the instances from your on-premises
network. To connect to instances in the public subnet, you must connect to the
instance's public IP address.
CreateRouteTable: Call it to create the Public Subnet Route Table. To enable communication by way of the internet gateway, add a route rule with destination = 0.0.0.0/0, and destination target = the internet gateway you created earlier.
CreateRouteTable: Call it again to create the Private Subnet Route Table. To enable communication by way of the NAT gateway, add a route rule with destination = 0.0.0.0/0, and destination target = the NAT gateway you created earlier.
Change the existing stateful ingress rules to use your on-premises network's CIDR as the source CIDR, instead of 0.0.0.0/0.
If you plan to launch Windows instances, add this stateful ingress rule: Source type = CIDR, source CIDR = your on-premises network on TCP, source port = all, destination port = 3389 (for RDP).
CreateSecurityList: Call it to create the Public Subnet Security List with these rules:
Stateful ingress: Source type = CIDR, source 0.0.0.0/0 on TCP, source port = all, destination port = 80 (HTTP)
Stateful ingress: Source type = CIDR, source 0.0.0.0/0 on TCP, source port = all, destination port = 443 (HTTPS)
Stateful egress: Destination type = CIDR, destination CIDR blocks of private subnets on TCP, source port = all, destination port = 1521 (for Oracle databases)
CreateSecurityList: Call it again to create the Private Subnet Security List with these rules:
Stateful ingress: Source type = CIDR, source CIDR blocks of public subnets on TCP, source port = all, destination port = 1521 (for Oracle databases)
Stateful ingress: Source type = CIDR, source CIDR blocks of private subnets on TCP, source port = all, destination port = 1521 (for Oracle databases)
Stateful egress: Destination type = CIDR, destination CIDR blocks of private subnets on TCP, source port = all, destination port = 1521 (for Oracle databases)
CreateSubnet: Call it to create regional public subnet. Include a DNS label for the subnet if you want the VCN Resolver to resolve hostnames for VNICs in the subnet. Use the Public Subnet Route Table you created earlier. Use both the default security list and the Public Subnet Security List that you created earlier. Use the default set of DHCP options.
CreateSubnet: Call it again to create regional private subnet. Include a DNS label for the subnet if you want the VCN Resolver to resolve hostnames for VNICs in the subnet. Use the Private Subnet Route Table you created earlier. Use both the default security list and the Private Subnet Security List that you created earlier. Use the default set of DHCP options.
CreateDrg: Creates a dynamic routing
gateway (DRG).
CreateCpe: Here you provide the IP address of the router at your end of the VPN (see Prerequisites).
CreateIPSecConnection: Here you provide the static routes for your
on-premises network (see Prerequisites). In
return, you receive the configuration information your network administrator needs
to configure your router. If you need that information later, you can get it with
GetIPSecConnectionDeviceConfig. For more information about the
configuration, see CPE Configuration.
First call GetRouteTable to get the Private Subnet Route Table. Then call UpdateRouteTable to add a route rule with destination = the on-premises network CIDR (10.0.0.0/16 in this example), and destination target = the DRG you created earlier.
LaunchInstance: Launch at least one instance in each subnet. By default, the instances in the public subnets are assigned public IP addresses. For more information, see Creating an Instance.
You can now communicate from your on-premises network with the instances in the public subnet over the internet gateway.
Important
Although you can launch instances into the private subnets, you can't
communicate with them from your on-premises network until your network administrator
configures your on-premises router (see CPE Configuration). After that,
your IPSec connection is up and running. You can confirm its status by using GetIPSecConnectionDeviceStatus. You can also confirm the IPSec connection is
up by connecting to the instances from your on-premises network.