Asterisk No sound behind OpenVPN

Asterisk Asterisk Support
1

Hi. I am having an Asterisk server in my local network configured fine.
I am trying to setup in my mobile the Bria Counterpath but without exposing Asterisk in Internet. So I have enable a VPN server in my router.
OpneVPN is configured and mobile connects fine. I see all machines with local ip.
Softphone also is registered with Asterisk, call start fine, I hear what they say to me but they cannot hear me at all.
So no outgoing sound from softphone. If I go to my local network and connect with VPN or not, softphone works fine.
I believe that my issue is that I have configured externip and localnet of asterisk wrong.
What I have done is this:

  1. In my router I have forwarded ports 5060,5061 - 10000:20000 - 5004:5062 to local asterisk ip. Which is 172.20.20.27
  2. My router uses private 192.168.1.x because it is after my internet provider
  3. In Asterisk I set:
    externhost: mydomain.dyndns.com ( because I use dynDNS, dynamic ip)
    localnet: 172.20.20.0/255.255.255.0   (my asterisk have static ip 172.20.20.27)
    localnet: 10.8.0.1/255.0.0.0   (for openVPN ip when connected)

VPN Subnet / Netmask is 172.20.21.0/255.255.255.0

Any help please here? I can’t find a solution for this and I am not a VOIP or Network expert

2

The issue might be related to the localnet and externhost settings in your Asterisk config.

You might need to adjust the localnet to include your OpenVPN subnet (172.20.21.0/24) instead of 10.8.0.1/8.

Also, double-check that externhost resolves to the correct public IP from your DynDNS setup.

Another thing to confirm is that the RTP port range (10000-20000) in rtp.conf matches the ports forwarded on your router.

Try enabling SIP debugging (sip set debug on) to verify if the RTP streams are using the expected IP addresses.

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