Hi, I too am having some problems getting this working properly. I have two ASUS RT AC5300 routers, At different locations. I have an IP Office and two IP phones. I created an OpenVPN tunnel between the two locations by configuring the router where the phones are as a client, and the router with the IP Office as the server. The phones can see the IP Office and register, but no voice traffic (dial-tones or speech) work from the phones. They do work when they are connected locally however. Is there something I need to add to the configuration to get this to work? The main network is 192.168.1.0/24 and the Remote office is 192.168.50.0/24. Here is a screenshot of the serving router's OpenVPN configuration and a drawing of the overall configuration:
Any ideas what is wrong are greatly appreciated!
