Setting up NAT Hairpinning between Two Subnets with OpenWrt

Setting up NAT Hairpinning between Two Subnets with OpenWrt

If you have a network with multiple subnets and want to access devices in one subnet from another subnet, you may need to set up NAT hairpinning. NAT hairpinning allows devices on the same network to communicate with each other using their public IP addresses, even if they are behind a NAT router. In this article, we will guide you through the process of setting up NAT hairpinning between two subnets using OpenWrt.

Step 1: Accessing OpenWrt Web Interface

To begin, make sure you are connected to your OpenWrt router's network. Open a web browser and enter the IP address of your router (usually 192.168.1.1) in the address bar. This will take you to the OpenWrt web interface.

Step 2: Enabling NAT Hairpinning

In the OpenWrt web interface, navigate to the "Network" tab and select "Firewall" from the dropdown menu. Scroll down to the "Port Forwards" section and click on "Add" to create a new port forward rule.

Fill in the following details:

• Name: Enter a name for the port forward rule.
• Protocol: Select "TCP+UDP" from the dropdown menu.
• External zone: Choose the zone that represents the network where the device you want to access is located.
• External port: Enter the port number you want to use for the access.
• Internal zone: Select the zone that represents the network where the device you want to access is located.
• Internal IP address: Enter the IP address of the device you want to access.
• Internal port: Enter the port number of the device you want to access.

Click on "Save & Apply" to save the port forward rule and enable NAT hairpinning.

Step 3: Testing NAT Hairpinning

Now that NAT hairpinning is enabled, you can test if devices in different subnets can communicate with each other using their public IP addresses.

On a device in one subnet, open a web browser and enter the public IP address of a device in the other subnet, along with the port number you specified in the port forward rule. If the communication is successful, you should be able to access the device's web interface or any other service running on that device.

Conclusion

Setting up NAT hairpinning between two subnets with OpenWrt allows devices in different subnets to communicate with each other using their public IP addresses. By following the steps outlined in this article, you can easily enable NAT hairpinning and establish seamless communication between devices on your network.