I have seen a lot of of WebRTC client libraries using public STUN server like below:
"stun.l.google.com:19302", "stun1.l.google.com:19302", "stun2.l.google.com:19302", "stun3.l.google.com:19302", "stun4.l.google.com:19302",
I am wondering if the servers above are dead? Because I have tried:
telnet stun.l.google.com 19302 telnet stun.l.google.com 3478
I get the following response:
telnet: connect to address 22.214.171.124: Operation timed out telnet: Unable to connect to remote host
Same thing happens to other google STUN server in list.
I couldn't get any response, does this mean the STUN servers from Google is not usable anymore?
My question is: Is telnet like the above the correct way to determine if a service is alive or not?