4 ms·

Does LAN work without internet connection?

capableweb 6y ago
Tested this a couple of years ago and Chrome prevented WebRTC connections from ever establishing if you're not connected to internet proper (it was doing some lookup to a Google domain before trying to actually create the WebRTC connection, even if I had nothing to do with Google, and stopped the attempt if it couldn't connect). Might have changed by now.
- dnautics 6y ago
  If memory serves me right it's a security issue, webrtc only allows connections when proper ssl certs exist on the initial brokered handshake, so you would only be able to do this if your lan has some sort of self signed ssl root cert and the cert placed in each machines authoritative cert stash.
  - lxgr 6y ago
    WebRTC doesn't use any public CA certificates to my knowledge. DTLS-SRTP uses self-signed certificates on both sides, with the certificate hashes or key fingerprints being included in the SDP signalling messages. Maybe you're thinking of the "secure origin" requirement? (The page hosting the JS needs to be a "trusted context", i.e. no file:// and no http:// http://)
    - dnautics 6y ago
      I'm referring to the secure origin requirement. Sorry I wasn't clear. Thank you for putting the correct label on it.
  - kingosticks 6y ago
    If you did need a certificate within your LAN, could you alternatively use Let's Encrypt with a DNS Challenge (if your provider has support)?
- Sean-Der 6y ago
  That might have been Google's STUN server? If this was required at one time this is now fixed! getUserMedia requires a secure domain (HTTPS or localhost) so LAN only video calls are kind of a PITA. You can easily do DataChannel only. For dev work I have a signaling server on a Class C address. Just for testing interop on Safari with my Linux box running signaling and WebRTC agent.
tehbeard 6y ago
You need at the very least, a mechanism to exchange ice candidates, data on which ip/port/protocol are available on each peer. So if u had a web server on that lan, yes. Otherwise u need a mechanism like QR codes or sneaker net a floppy disk with the details to the other peers.
- capableweb 6y ago
  This is the assumption I had as well last time I tried it, but it's not like that, at least last time I tried it a couple of years ago. Might have changed by now.
miyuru 6y ago
In case of IPv6, even if the users have public IPv6 address and is in the same network, traffic does not leave the network. So if you are sharing the same LAN, it does not need internet. This is because the large IP address space make routing efficient, without the use of NAT.

Tested this a couple of years ago and Chrome prevented WebRTC connections from ever establishing if you're not connected to internet proper (it was doing some lookup to a Google domain before trying to actually create the WebRTC connection, even if I had nothing to do with Google, and stopped the attempt if it couldn't connect). Might have changed by now.

dnautics 6y ago
If memory serves me right it's a security issue, webrtc only allows connections when proper ssl certs exist on the initial brokered handshake, so you would only be able to do this if your lan has some sort of self signed ssl root cert and the cert placed in each machines authoritative cert stash.
- lxgr 6y ago
  WebRTC doesn't use any public CA certificates to my knowledge. DTLS-SRTP uses self-signed certificates on both sides, with the certificate hashes or key fingerprints being included in the SDP signalling messages. Maybe you're thinking of the "secure origin" requirement? (The page hosting the JS needs to be a "trusted context", i.e. no file:// and no http:// http://)
  - dnautics 6y ago
    I'm referring to the secure origin requirement. Sorry I wasn't clear. Thank you for putting the correct label on it.
- kingosticks 6y ago
  If you did need a certificate within your LAN, could you alternatively use Let's Encrypt with a DNS Challenge (if your provider has support)?
Sean-Der 6y ago
That might have been Google's STUN server? If this was required at one time this is now fixed! getUserMedia requires a secure domain (HTTPS or localhost) so LAN only video calls are kind of a PITA. You can easily do DataChannel only. For dev work I have a signaling server on a Class C address. Just for testing interop on Safari with my Linux box running signaling and WebRTC agent.

tehbeard 6y ago

You need at the very least, a mechanism to exchange ice candidates, data on which ip/port/protocol are available on each peer. So if u had a web server on that lan, yes. Otherwise u need a mechanism like QR codes or sneaker net a floppy disk with the details to the other peers.

capableweb 6y ago
This is the assumption I had as well last time I tried it, but it's not like that, at least last time I tried it a couple of years ago. Might have changed by now.

miyuru 6y ago

In case of IPv6, even if the users have public IPv6 address and is in the same network, traffic does not leave the network. So if you are sharing the same LAN, it does not need internet. This is because the large IP address space make routing efficient, without the use of NAT.