[WebRTC] closed: deadline exceeded while waiting connection

[derekcct2]

Question

Before version 1.3.0 of mediaMTX,
if the webrtcICEHostNAT1to1IPs was set to a fixed IP, such as 192.168.1.100, everything worked fine.
However, starting from version 1.3.0, webrtcICEHostNAT1to1IPs was changed to webrtcAdditionalHosts.
If webrtcAdditionalHosts is set to 192.168.1.100, an error occurs stating "[WebRTC] closed: deadline exceeded while waiting connection," and the video cannot be seen through WebRTC.
Is this behavior normal?
My goal is to set webrtcAdditionalHosts to a fixed IP, DNS, and internal IP, but whenever I include an IP in the settings, this error occurs. Did I configure something incorrectly?

[derekcct2]

Here are the configurations and logs from when I ran the executable file of MediaMTX version 1.6.0 on Windows.
In the mediamtx.yml, whenever I change webrtcAdditionalHosts: [192.168.70.46] to webrtcAdditionalHosts: [], I can successfully view the stream's video from http ://192.168.70.46:8889/test.
log.zip

[aler9]

Hello, the other change that was introduced in v1.3.0 was that WebRTC peer connections are now established by using a single, fixed port, that can be set through webrtcLocalUDPAddress or webrtcLocalTCPAddress and by default is 8189.

This port must be opened or forwarded to users in the same way that port in webrtcAddress is (8889), otherwise a connection cannot be established.

The advantage of this method lies in the fact that a STUN server is not necessary anymore and therefore no third-party service is contacted whenever you want to use WebRTC.

If you liked the old method better, in which a STUN server and a random UDP port were used in order to establish connection, and no port forwarding was needed, you can re-enable it by following instructions in the README:

# STUN servers allows to obtain and share the public IP of the server.
webrtcICEServers2:
  - url: stun:stun.l.google.com:19302

random port and public IP address will appear in the SDP:

a=candidate:3901994122 1 udp 1694498815 x.x.x.95 48537 typ srflx raddr 0.0.0.0 rport 48537
a=candidate:3901994122 2 udp 1694498815 x.x.x.95 48537 typ srflx raddr 0.0.0.0 rport 48537

[derekcct2]

Thank you for your explanation.
As you mentioned, when I set webrtcICEServers2 to stun:stun.l.google.com:19302, I am able to successfully establish a WebRTC connection. However, I am curious about something. When webrtcAdditionalHosts is not set, the WebRTC connection works fine regardless of whether webrtcICEServers2 is set or not.
But if webrtcAdditionalHosts is set to a fixed IP other than 127.0.0.1, then webrtcICEServers2 must be set, otherwise, the connection fails. Why is this happening?
I am running WebRTC on Windows as an executable file, so there should be no firewall blocking the 8189 port.
Does this mean that if I want to set webrtcAdditionalHosts, whether it's a fixed IP or a DNS, I must also fill in webrtcICEServers2?

[aler9]

Does this mean that if I want to set webrtcAdditionalHosts, whether it's a fixed IP or a DNS, I must also fill in webrtcICEServers2?

No, it means that your users are unable to access the server through host contained in webrtcAdditionalHosts and the port in webrtcLocalUDPAddress, which is a UDP port and might be as well blocked by the Windows firewall by default. I cannot say anything else since a network dump would be needed for further analysis.

When you fill webrtcICEServers2, you are enabling the legacy connection mechanism, which runs in parallel to the new one. Whichever is the first to work, it is used for exchanging packets.