How to identify a 301 redirect from a third party domain?

Question

PHP

Hello!
In general, the situation is as follows:
From one site they periodically put 301 redirects to my site, I have problems with this of an intra-site nature and with users.
I tried to contact the admins of that site (from which users are being redirected), but in response, silence.
Is it possible to somehow determine that the user came from a redirect from a third-party site.
It is desirable to implement this in PHP. If it's not possible with php, then maybe with nginx.

Answer 1

Check $_SERVER['HTTP_REFERER']

Answer 2

This is a task, not a question.
It would be more correct to configure the nginx config to reject requests from an incomprehensible domain.