▲ 6 ▼ openup - utiliy that opens port forwards via upnp in Go

When is this useful? If you ever want to expose an IP address on a LAN to the internet, you can set a port forward with your router via UPnP that will port forward from the router (public IP) to the machine on the local network (192.168.x.x address).Then you can hit the external IP address at the given port and it will get forwarded to the given machine on the local network.