IP forwarding enables the virtual machine a network interface is attached to to:
- Receive network traffic not destined for one of the IP addresses assigned to any of the IP configurations assigned to the network interface.
- Send network traffic with a different source IP address than the one assigned to one of a network interface’s IP configurations.
The setting must be enabled for every network interface that is attached to the virtual machine that receives traffic that the virtual machine needs to forward. A virtual machine can forward traffic whether it has multiple network interfaces or a single network interface attached to it. While IP forwarding is an Azure setting, the virtual machine must also run an application able to forward the traffic, such as firewall, WAN optimization, and load balancing applications. When a virtual machine is running network applications, the virtual machine is often referred to as a network virtual appliance. You can view a list of ready to deploy network virtual appliances in the Azure Marketplace. IP forwarding is typically used with user-defined routes.
- In the box that contains the text “Search resources' at the top of the Azure portal, type “network interfaces”.
- When “network interfaces” appears in the search results, select it.
- Select the network interface that you want to enable or disable IP forwarding for.
- Select IP configurations in the “Settings” section.
- Select “Enabled” or “Disabled” (default setting) to change the setting.
- Select “Save.”