For enabling peers, that are behind NAT (Private LANs), to create WebRTC PeerConnections with Janus, it's recommended to setup a TURN server. It's also recommended that your TURN server is running on the Docker host
network.
Hence we will your Instrumentos docker images:
docker run -d \
--name="coturn" \
--restart="always" \
--net=host \
instrumentisto/coturn -n \
--lt-cred-mech --fingerprint \
--no-multicast-peers \
--cli-password=MyTopSecret \
--no-tlsv1 \
--no-tlsv1_1 \
--fingerprint \
--lt-cred-mech \
--verbose \
--user=SuperUser:MyTopSecret \
--server-name=your_domain \
--realm=your_domain \
--listening-ip='$(detect-external-ip)' \
--min-port=10200 \
--max-port=49200
To test your TURN server, check this post.