if you want to make a point to point call from TEX0 to another, there are two secanrios:
1- inside LAN: you just need basic configuration and then test
2- outside LAN: you need to
1. Configure the TE10 with a private IP address
2. NAT the private IP address with the public IP address that you will get from the internet provider (Firewall side)
3. Activate the port in the below lists on the Firewall side :





or for demo