How does the 1whois.ru service determine server type, version?

Question

Domain name market

Hello. There is such a service 1whois.ru, which shows various information on the domain. Among other things, it sometimes shows server type (nginx, IIS) , version (here it can be as a language or framework), and sometimes even shows CMS . Everything I checked was accurate. For example, for one of my sites on node/express, I defined version = express. Question: how can such data be determined?

Answer 1

The server type is passed in every server response when the site is visited.
CMS and the features of their definition depend on the cms itself. Some at the address of the admin panel, some at the folders in the addresses of the pictures, for example, some in the code they write in plain text, etc. The version is often written on the admin page, or there are xcrf vulnerabilities showing additional information.