Problem with BBB 2.5.6 and coturn behind NAT

[glu...@gmail.com]

I have an installation with BBB and coturn on the same local network 10.99.220.x behind NAT:

BBB Server (wuth Greenlight):
Hostname: bbb4.mydomain.com
IP-extern: 83.xxx.yyy.169
IP-intern: 10.99.220.69
OS: Ubuntu 20.04.4
BBB version: 2.5.6

TURN Server
Hostname: turn1.mydomain.com
IP-extern: 83.xxx.yyy.171
IP-intern: 10.99.220.71
OS: Ubuntu 20.04.4
Turn version: coturn  4.5.1.1

On BBB and TURN Server all ports are open and mapped to the external IP address.

When connecting from external to BBB Server Audio and Video (Webcam) connection works fine, but only when the connection from the client is done directly without using the TURN server. When forcing Firefox to use TURN by setting media.peerconnection.ice.relay_only to true Audio connection works but Video (Webcam) does not work and returns an ICE 1107 error after a couple of seconds. See att1.png (Video) and att2.png (Audio).

I checked if there is an incoming connection on the BBB Server on the port shown in Firefox with about:webrtc when starting the Webcam. Using netstat -tulpn I can see an active connection to process mediasoup-wo.

I did the same tests on Firefox and Chrome. With Chrome I use the extension WebRTC Control 0.3.0 and disabled non proxied udp. The result is the same as with Firefox. Additionally webrtc-internals shows an icecandidateerror (error_text: TURN host lookup received error. error_code: 701) - see att5.png

My assumption is that everything is OK with the TURN server and the network, but obviously there is a problem with mediasoup. However the mediasoup log-file /var/log/bbb-webrtc-sfu/bbb-webrtc-sfu.log does not show any hints whats wrong (see att3.txt)

I also tried to use a local DNS server to resolve the bbb4.mydomain.com to the internal IP 10.99.220.69 instead of the external address. Same for the TURN server. However it did not help to solve the problem.

It would be great if one of the developers familiar with mediasoup could have look at this issue.