1. Directly open the URL to be queried with a browser, such as https://baidu.com, and then click
2. Turn on the [Link is secure] option
3. Look at the words [Certificate is valid] below, click to see the details
Note that if we are developing a project, our front-end web page address is https://a.test.com. The backend service used at the same time is https://b.test.com. Since the former can be accessed in the browser, it can be viewed by the above method.
But the service provided by the backend is 404 when directly accessed by the browser. So what do you think? The answer is, the same way. Even if it is a 404 URL, as long as the domain name is resolved, this method can be used.
Knowledge point: Learn to analyze whether a domain name has been resolved, that is, whether the DNS resolution can resolve it.
