Put your phone into a wireless microphone WITH Bi-directional audio supports
It supports UPnP port forwarding. If you can access your gateway via WAN, and the UPnP on your gateway is opened, you can also use WAN Url from WAN to visit Wireless MIC Server. And also supports user name and password authentication, default username and password are admin, you can modify the settings inside.
"Wireless MIC" provides full IPv6 support!