How do I troubleshoot the failure to connect a client to a server?

Problem description

The client cannot connect to the server.

Possible cause

Real-Time Communication (RTC) requires UDP port 80, 443, 3478, or 50000. The connection by using these UDP ports may fail because the firewall is enabled or the connection is restricted by a routing policy.

Solution

For devices that run the Windows or Linux operating system, run the netcat command to check whether the preceding UDP ports can be used.

Check whether the firewall or routing policy restricts the use of the preceding UDP ports.