How to exclude the indexing of the developed site by search engines?

Question

Google

Good afternoon!
This is the second time I have had to change the domain for the test version of the site. First, a new site, new.site.ru, was developed, later it was indexed by search engines, although no one did to add it to the search base, and there is a robot.txt file. As a result, they redirected everyone via 301 redirect to the main site, the domain was replaced with www2.site.ru, but it suffered the same fate (after 3 months).
Password a website with htpasswd? are there other ways?

Answer 1

At least robots.txt with content

User-agent: *
Disallow: /

For good, this is enough.
But you can additionally close basic auth
By the way, in order for the site to appear in search engines, there is no need to add it manually.
Branded browsers, Yandex metrics, transitions to external sites where the metric is set - and search engines already know your url)

Answer 2

firstly, do not put links on the new site that are accessible to search engine robots, then the site simply cannot be found without knowing about it.
secondly, the presence of the robots.txt file will not give anything, you need to write something like Disallow: / in it (for more details, look for "robots.txt directives")
and thirdly, try the stub page.

Answer 3

everything was done:
User-agent: *
Disallow: /
yes, most likely, because of the metric that was on the main site and was transferred to this one at the time of synchronization of the contents of the real site and the development site.
you will have to make protection through htpasswd

Answer 4

The robots.txt file is used to partially control the indexing of the site by search robots. This file consists of a set of instructions for search engines to specify which files, pages, or directories on a site should not be indexed.
But search engines are not required to target this file!
It is necessary to close the developed site by password or IP address

Answer 5

https://yoast.com/articles/robots-meta-tags/
This is a shortcut for noindex,nofollow, or basically saying to search engines: don't do anything with this page at all.