How to set up Port Forwarding to a host located in an OpenVPN network?

Question

linux

Hello,
I set up OpenVPN on VDS, connected an IP-PBX to the server via OpenVPN, connected the Internet using the OpenVPN server as a gateway. Now I want to set up a SIP trunk to a SIP provider. There are problems with the configuration, please help to solve this problem.
eth0 - Internet adapter
IP: 62.76.180.234
tun0 - OpenVPN adapter
IP:10.0.0.1
Gateway: 10.0.02
IP PBX
IP: 10.0.0.6
Gateway:10.0.0.5

Answer 1

And what exactly is the problem? Write some rules for dst-nat entry to iptables and src-nat for exit. The search is full of such instructions.

Answer 2

I'm using firwalld, the problem is that I've created all the necessary rules for port forward and NAT but they don't apply. Moreover, the softphone on the PC connects without problems, but the Yeastar IP-PBX does not.