How do I check which ports are open on the Alibaba Cloud host?
After opening the internal network service monitoring port, your own host can check whether the firewall and security group allow the port to accept public network access.
Other people's hosts can use the port scanning tool, or use the telnet command to try to connect. If the connection is successful, it means that the security group is released, the firewall is released, and the intranet has a service listening port.