I need rtp only via VPN not normal network

I doing very strange configuration and I realized that there is TLS and other protocols to secure SIP and RTP but …

I have machine with IP 192.168.0.1/24 on it i have installed Asterisk and OpenVPN with 10.0.0.1/24
Asterisk is binded only to 10.0.0.1 ip address, my mobile devices are in this same network and connecting to VPN server.
SIP signalings using VPN network, but RTP are send to local network and I dont know why

What addresses are the mobile devices sending in their SDP?

What address is Asterisk is sending in its SDP?

If the mobile devices are not sending the VPN address, but Asterisk is, you may find that enabling comedia (details depend on whether you are using chan_sip, or chan_pjsip), may work round the problem with the remote devices.

Mobile devices are sending everything to VPN address of Asterisk,

In that case Asterisk is working correctly. You didn’t say where the mobile devices were telling Asterisk to send media.

Everything without rtp