Configure network routing

Introduction

In modern cloud environments, controlling how network traffic flows is just as important as securing the workloads themselves. In this guide, we’ll configure custom network routing in Azure by creating route tables, associating them with subnets, and directing outbound traffic through an Azure Firewall for centralized inspection and filtering. This hands-on exercise demonstrates practical cloud networking and security skills that are essential for designing secure, enterprise-grade Azure infrastructures.

Scenario

To ensure the firewall policies are enforced, outbound application traffic must be routed through the firewall. You identify these requirements.

• A route table is required. This route table will be associated with the frontend and backend subnets.
• A route is required to filter all outbound IP traffic from the subnets to the firewall. The firewall’s private IP address will be used.

Skilling tasks

• Create and configure a route table.
• Link a route table to a subnet.

Exercise instructions

Create a route table

Azure automatically creates a route table for each subnet within an Azure virtual network. The route table includes the default system routes. You can create route tables and routes to override Azure’s default system routes.

Record the private IP address of app-vnet-firewall

1.In the search box at the top of the portal, enter Firewall. Select Firewall in the search results.

2.Select app-vnet-firewall.

3.Select Overview and record the Private IP address.

Add the route table

1.In the search box, enter Route tables. When Route table appears in the search results, select it.

2.In the Route table page, select + Create and create the route table.

Property	Value
Subscription	Select your subscription
Resource group	RG1
Region	East US
Name	app-vnet-firewall-rt

3.Select Review + create and then select Create.

4.Wait for the route table to deploy, then select Go to resource.

Associate the route table to the subnets

1.In the portal, continue working with the route table, select app-vnet-firewall-rt.

2.In the Settings blade, select Subnets and then + Associate.

3.Configure an association to the frontend subnet, then select OK.

Property	Value
Virtual network	app-vnet (RG1)
Subnet	frontend

4.Configure an association to the backend subnet, then select OK.

Property	Value
Virtual network	app-vnet (RG1)
Subnet	backend

Create a route in the route table

1.In the portal, continue working with the route table, select app-vnet-firewall-rt.

2.In the Settings blade, select Routes and then + Add.

3.Configure the route, then select Add.

Property	Value
Route name	outbound-firewall
Destination type	IP addresses
Destination IP addresses/CIDR range	0.0.0.0/0
Next hop type	Virtual appliance
Next hop address	private IP address of the firewall

Key takeaways

Here are the main takeaways:

• Network traffic in Azure is automatically routed across Azure subnets, virtual networks, and on-premises networks. System routes control this routing.
• User-defined routes override the default system routes so traffic can be routed through a network virtual appliances (NVAs).
• Network virtual appliances (NVAs) control the flow of network traffic. Examples of NVAs are firewalls, load balancers, and routers.
• Route tables contain routing information and are associated with a subnet.

Summary

In this exercise, we configured Azure network routing to ensure outbound traffic is securely inspected through an Azure Firewall. We created a custom route table, associated it with the frontend and backend subnets, and added a user-defined route that forwards all outbound traffic to the firewall’s private IP address. This setup demonstrates how Azure route tables and network virtual appliances work together to provide centralized traffic control, improved security, and enterprise-grade network management.