Truy cập http://www.canyouseeme.org bằng trình duyệt web. Nhập cổng. Nhấp vào Check Port (Kiểm tra cổng).

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
You can use it to see if a port on your computer or network is accessible on the internet. The website will automatically detect your IP address and display it in the "Your IP" box. There are many different sites you can use to check for an open port. Search for "open port check tool" in your favorite search engine to find an alternative, if desired. Type the port you want to check (e.g., 22 for SSH) into the "Port to Check" box. If the port is open and available, you'll see a confirmation messa