Chevillette
Tirez la bobinette et la chevillette cherra
You have two websites, one authenticated, the other is a preprod, almost public.
If your IP and user agent was seen in A server, you are whitelisted is site B.
It's a basic anti bot tools, not a real security tool, like basic auth or oauth2.
This tool doesn't handle very well coworking spaces or any public access point.
Demo
cd demo
Launch services
docker compose up -d
Test protected website B
docker run client curl nginx-b
It should 403
Unlock with website A
docker run client curl nginx-a
Test website B again
docker run client curl nginx-b
It should b 200