How to make LDAP authorization on web resources with two domain controllers?

Question

LDAP

Hello!
1) domain org.domain.ru - created first with its own forest, etc.
2) then domain.ru was created, also with its own forest.
The organization has resources with LDAP authorization.
How to properly organize LDAP authorization -
=> The user enters a login and password into the web form -> check on domain.ru if there is no such pair, then on the second domain.
Or you can configure unilateral synchronization of only account groups from org.domain.ru to domain.ru
Nothing can be rewritten in the web form.

Answer 1

Got it!
In order for the web application to work with several domains, it is necessary to configure access to the global catalog on port 3268.
ldap://domain.ru:3128/
More details here
And also here

Answer 2

Raise trust between forests and check...