Problem with nginx reverse proxy binding independent domain name?

Question

Scenario: A multi-user system binds an independent domain name to a user. Primary domain name: www.xxx.com/username Independent domain name: www.username.com (any) Problem: Since the multi-user system server is in China, the user's independent domain name cannot be directly resolved Come over so there is a foreign host as a reverse proxy...

仅有的幸福 · Answer

server {
    listen 80 default_server;

    location / {
        proxy_set_header Host $host;
        proxy_redirect off;
        proxy_pass http://<国内服务器>/;
    }
}

Then the domestic server first verifies that the source IP of the request is the specified IP (preventing the user from directly resolving the domain name to the domestic server), and then displays the user's site based on the Host in the request.

高洛峰 · Answer

It is similar to the LOFTER blog. How is this achieved?