Hairpin NAT (also known as NAT loopback and Hairpinning) is an advanced network feature that allows you to access port-forwarded devices from inside the network using an external IP address. As of eeroOS v3.3.0 or later, this feature is automatically enabled for all networks. You can check your network version by following our update guide.
To use this feature, you'll need to configure a port forward on your network. Make sure the port isn't blocked by another device (such as an upstream router). See How do I configure port forwarding?