VoIP Calls no Sound on both sides (Maybe RTP issue)

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hans2020dieter
OpenVpn Newbie
Posts: 2
Joined: Sat Jun 20, 2020 10:56 pm

VoIP Calls no Sound on both sides (Maybe RTP issue)

Post by hans2020dieter » Sat Jun 20, 2020 11:34 pm

Hi,

I'm building an OpenVPN Server to connect from the Internet into my Home-LAN and make phone calls using SIP.
I've got an AVM Fritzbox Home-Router from my ISP which has a build in SIP-Server for Softphones.
I use Softphone Software like Linphone and Jitsi.
In my LAN SIP Calls work fine with no problems.

But: when I connect from outside to the OpenVPN Server and trying to make calls I got issues.
  • The connection to the VPN could be established.
  • My Softphone can actually login to the SIP-Server of my fritzbox.
  • So I try to make a call and it works.
  • The other side received my call and when I answer it the call is established (means SIP-protocol might work fine).
  • But!: the call has NO SOUND AT ALL on both sides :( (I suggest that might be a RTP problem :?: ).
I used that OpenVPN Install guide: https://www.cyberciti.biz/faq/ubuntu-20 ... 5-minutes/

Has someone any idea what can cause that rtp doesn't work?
Could it be a routing issue? Or a port issue?

Thanks!

hans2020dieter
OpenVpn Newbie
Posts: 2
Joined: Sat Jun 20, 2020 10:56 pm

Re: VoIP Calls no Sound on both sides (Maybe RTP issue)

Post by hans2020dieter » Sun Jun 21, 2020 1:14 pm

OMG :o .......... The solution was so simple :lol:
Because OpenVPN routes to my Local Network I can reach fritzbox. But: fritzbox cant reach openvpn because there is no route.......
So, I went to Fritzbox Settings/Home Network/Networksettings and set a static route.
Network: (The OpenVPN-Subnet in my case 10.8.0.0)
The Netmask: (In my case 255.255.255.0)
And the Gateway: (In my case the 192.168.X.X address of my OpenVPN Server)
Thats all..... Now everything works fine!!!! :D

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