So my DSL Speed was ultra-mega-horrible and i decided to go LTE, Congstar Homespot to be precise.

Set up my VR900v as 3G/4G-Router

i bought a SIM, and a LTE dongle, ZTE MF823 and i was happy: Decent internet speed.

But i can´t get VOIP to work. i´m with Voip2gsm.eu.

I attached dongle to Telekom APN with public IP.

The problem is that the dongle itself is attached to the APN and has the public IP.

The router is behind the USB Dongle and doesn´t know about the public IP.

In effect i can call outside but cannot be called.

I don´t know how to fix this. I tried SIP-ALG, Enabled UPnP on VR900v and Dongle, ...but i don´t know how to add a STUN-server which i think would be necessary.

There are no SIP settings in dongle.

Anyone knows help? I love my VR900v and don´t want other if possible.

Thank you.